diff --git a/app/controllers/admin/conferences_controller.rb b/app/controllers/admin/conferences_controller.rb
index cafc2b32..1def3c5b 100644
--- a/app/controllers/admin/conferences_controller.rb
+++ b/app/controllers/admin/conferences_controller.rb
@@ -8,7 +8,7 @@ module Admin
 
     def index
       # Redirect to new form if there is no conference
-      if Conference.count == 0
+      if Conference.none?
         redirect_to new_admin_conference_path
         return
       end
diff --git a/app/controllers/admin/roles_controller.rb b/app/controllers/admin/roles_controller.rb
index ca455dce..d69e1ab1 100644
--- a/app/controllers/admin/roles_controller.rb
+++ b/app/controllers/admin/roles_controller.rb
@@ -69,7 +69,7 @@ module Admin
       end
 
       # The conference must have at least 1 organizer
-      if @role.name == 'organizer' && state == 'false' && @role.users.count == 1
+      if @role.name == 'organizer' && state == 'false' && @role.users.one?
         redirect_to admin_conference_role_path(@conference.short_title, @role.name),
                     error: 'The conference must have at least 1 organizer!'
         return
diff --git a/app/controllers/admin/volunteers_controller.rb b/app/controllers/admin/volunteers_controller.rb
index b0b85ffc..35629345 100644
--- a/app/controllers/admin/volunteers_controller.rb
+++ b/app/controllers/admin/volunteers_controller.rb
@@ -3,6 +3,7 @@
 module Admin
   class VolunteersController < Admin::BaseController
     include VolunteersHelper
+
     load_and_authorize_resource :conference, find_by: :short_title
 
     def index
diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 93105587..315c4e30 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -3,6 +3,7 @@
 class ApplicationController < ActionController::Base
   before_action :set_paper_trail_whodunnit
   include ApplicationHelper
+
   add_flash_types :error
   protect_from_forgery with: :exception, prepend: true
   before_action :store_location
diff --git a/app/controllers/conferences_controller.rb b/app/controllers/conferences_controller.rb
index 8a4262f1..43809551 100644
--- a/app/controllers/conferences_controller.rb
+++ b/app/controllers/conferences_controller.rb
@@ -50,14 +50,14 @@ class ConferencesController < ApplicationController
         ).order('tracks.name')
       end
       if splashpage.include_booths
-        @booths = @conference.confirmed_booths.order('title')
+        @booths = @conference.confirmed_booths.order(:title)
       end
     end
     if splashpage.include_registrations || splashpage.include_tickets
-      @tickets = @conference.tickets.order('price_cents')
+      @tickets = @conference.tickets.order(:price_cents)
     end
     if splashpage.include_lodgings
-      @lodgings = @conference.lodgings.order('name')
+      @lodgings = @conference.lodgings.order(:name)
     end
     if splashpage.include_sponsors
       @sponsorship_levels = @conference.sponsorship_levels.eager_load(
diff --git a/app/helpers/events_helper.rb b/app/helpers/events_helper.rb
index ddb16e4c..b2768317 100644
--- a/app/helpers/events_helper.rb
+++ b/app/helpers/events_helper.rb
@@ -39,7 +39,7 @@ module EventsHelper
   end
 
   def canceled_replacement_event_label(event, event_schedule, *label_classes)
-    if event.state == 'canceled' || event.state == 'withdrawn'
+    if ['canceled', 'withdrawn'].include?(event.state)
       content_tag :span, 'CANCELED', class: (['label', 'label-danger'] + label_classes)
     elsif event_schedule.present? && event_schedule.replacement?(@withdrawn_event_schedules)
       content_tag :span, 'REPLACEMENT', class: (['label', 'label-info'] + label_classes)
diff --git a/app/models/admin_ability.rb b/app/models/admin_ability.rb
index 67bf6cfe..34bccc51 100644
--- a/app/models/admin_ability.rb
+++ b/app/models/admin_ability.rb
@@ -141,7 +141,7 @@ class AdminAbility
 
     # Abilities for Role (Conference resource)
     can [:index, :show], Role do |role|
-      role.resource_type == 'Conference' || role.resource_type == 'Track'
+      ['Conference', 'Track'].include?(role.resource_type)
     end
 
     can [:edit, :update, :toggle_user], Role do |role|
@@ -180,7 +180,7 @@ class AdminAbility
 
     # Abilities for Role (Conference resource)
     can [:index, :show], Role do |role|
-      role.resource_type == 'Conference' || role.resource_type == 'Track'
+      ['Conference', 'Track'].include?(role.resource_type)
     end
     # Can add or remove users from role, when user has that same role for the conference
     # Eg. If you are member of the CfP team, you can add more CfP team members (add users to the role 'CfP')
@@ -218,7 +218,7 @@ class AdminAbility
 
     # Abilities for Role (Conference resource)
     can [:index, :show], Role do |role|
-      role.resource_type == 'Conference' || role.resource_type == 'Track'
+      ['Conference', 'Track'].include?(role.resource_type)
     end
     # Can add or remove users from role, when user has that same role for the conference
     # Eg. If you are member of the CfP team, you can add more CfP team members (add users to the role 'CfP')
@@ -242,7 +242,7 @@ class AdminAbility
 
     # Abilities for Role (Conference resource)
     can [:index, :show], Role do |role|
-      role.resource_type == 'Conference' || role.resource_type == 'Track'
+      ['Conference', 'Track'].include?(role.resource_type)
     end
     # Can add or remove users from role, when user has that same role for the conference
     # Eg. If you are member of the CfP team, you can add more CfP team members (add users to the role 'CfP')
@@ -278,7 +278,7 @@ class AdminAbility
 
     # Show Roles in the admin sidebar and allow authorization of the index action
     can [:index, :show], Role do |role|
-      role.resource_type == 'Conference' || role.resource_type == 'Track'
+      ['Conference', 'Track'].include?(role.resource_type)
     end
 
     can :toggle_user, Role do |role|
diff --git a/app/models/booth.rb b/app/models/booth.rb
index 85c6c7a8..06357f0e 100644
--- a/app/models/booth.rb
+++ b/app/models/booth.rb
@@ -2,6 +2,7 @@
 
 class Booth < ApplicationRecord
   include ActiveRecord::Transitions
+
   has_paper_trail ignore: [:updated_at], meta: { conference_id: :conference_id }
 
   belongs_to :conference
diff --git a/app/models/comment.rb b/app/models/comment.rb
index ee1a07a8..0b4e6800 100644
--- a/app/models/comment.rb
+++ b/app/models/comment.rb
@@ -35,13 +35,13 @@ class Comment < ApplicationRecord
   # Helper class method to lookup all comments assigned
   # to all commentable types for a given user.
   scope :find_comments_by_user, lambda { |user|
-    where(user_id: user.id).order('created_at DESC')
+    where(user_id: user.id).order(created_at: :desc)
   }
 
   # Helper class method to look up all comments for
   # commentable class name and commentable id.
   scope :find_comments_for_commentable, lambda { |commentable_str, commentable_id|
-    where(commentable_type: commentable_str.to_s, commentable_id: commentable_id).order('created_at DESC')
+    where(commentable_type: commentable_str.to_s, commentable_id: commentable_id).order(created_at: :desc)
   }
 
   scope :find_since_last_login, lambda { |user|
diff --git a/app/models/conference.rb b/app/models/conference.rb
index 2e63e4ee..46505572 100644
--- a/app/models/conference.rb
+++ b/app/models/conference.rb
@@ -2,13 +2,14 @@
 
 class Conference < ApplicationRecord
   include RevisionCount
+
   require 'uri'
   serialize :events_per_week, Hash
   # Needed to call 'Conference.with_role' in /models/ability.rb
   # Dependent destroy will fail as roles#destroy will be cancelled,hence delete_all
   resourcify :roles, dependent: :delete_all
 
-  default_scope { order('start_date DESC') }
+  default_scope { order(start_date: :desc) }
   scope :upcoming, (-> { where(end_date: Date.current..) })
   scope :past, (-> { where(end_date: ...Date.current) })
 
@@ -39,7 +40,7 @@ class Conference < ApplicationRecord
   has_many :participants, through: :registrations, source: :user
   has_many :vdays, dependent: :destroy
   has_many :vpositions, dependent: :destroy
-  has_many :sponsorship_levels, -> { order('position ASC') }, dependent: :destroy
+  has_many :sponsorship_levels, -> { order(:position) }, dependent: :destroy
   has_many :sponsors, dependent: :destroy
   has_many :commercials, as: :commercialable, dependent: :destroy
   has_many :subscriptions, dependent: :destroy
@@ -107,7 +108,7 @@ class Conference < ApplicationRecord
   # * +false+ -> If the user is registered
   # * +true+ - If the user isn't registered
   def user_registered? user
-    user.present? && registrations.where(user_id: user.id).count > 0
+    user.present? && registrations.where(user_id: user.id).any?
   end
 
   ##
@@ -350,7 +351,7 @@ class Conference < ApplicationRecord
   # * +hash+ -> user: submissions
   def self.get_top_submitter(limit = 5)
     submitter = EventUser.select(:user_id).where('event_role = ?', 'submitter').limit(limit).group(:user_id)
-    counter = submitter.order('count_all desc').count(:all)
+    counter = submitter.order(count_all: :desc).count(:all)
     calculate_user_submission_hash(submitter, counter)
   end
 
@@ -363,7 +364,7 @@ class Conference < ApplicationRecord
     submitter = EventUser.joins(:event).select(:user_id)
         .where('event_role = ? and program_id = ?', 'submitter', Conference.find(id).program.id)
         .limit(limit).group(:user_id)
-    counter = submitter.order('count_all desc').count(:all)
+    counter = submitter.order(count_all: :desc).count(:all)
     Conference.calculate_user_submission_hash(submitter, counter)
   end
 
@@ -921,7 +922,7 @@ class Conference < ApplicationRecord
   # * +True+ -> One difficulty level or more
   # * +False+ -> No diffculty level
   def difficulty_levels_set?
-    program.difficulty_levels.count > 0
+    program.difficulty_levels.any?
   end
 
   ##
@@ -931,7 +932,7 @@ class Conference < ApplicationRecord
   # * +True+ -> One difficulty level or more
   # * +False+ -> No diffculty level
   def event_types_set?
-    program.event_types.count > 0
+    program.event_types.any?
   end
 
   ##
@@ -941,7 +942,7 @@ class Conference < ApplicationRecord
   # * +True+ -> One track or more
   # * +False+ -> No track
   def tracks_set?
-    program.tracks.count > 0
+    program.tracks.any?
   end
 
   ##
@@ -951,7 +952,7 @@ class Conference < ApplicationRecord
   # * +True+ -> One room or more
   # * +False+ -> No room
   def rooms_set?
-    venue.present? && venue.rooms.count > 0
+    venue.present? && venue.rooms.any?
   end
 
   # Checks if the conference has a venue object.
diff --git a/app/models/event.rb b/app/models/event.rb
index dc7202c2..82f8204b 100644
--- a/app/models/event.rb
+++ b/app/models/event.rb
@@ -4,6 +4,7 @@ class Event < ApplicationRecord
   include ActionView::Helpers::NumberHelper # for number_with_precision
   include ActiveRecord::Transitions
   include RevisionCount
+
   has_paper_trail on: [:create, :update], ignore: [:updated_at, :guid, :week], meta: { conference_id: :conference_id }
 
   acts_as_commentable
diff --git a/app/models/event_schedule.rb b/app/models/event_schedule.rb
index 8c5e9753..32ec8b4f 100644
--- a/app/models/event_schedule.rb
+++ b/app/models/event_schedule.rb
@@ -82,13 +82,13 @@ class EventSchedule < ApplicationRecord
   end
 
   def start_after_end_hour
-    return unless event && start_time && event.program&.conference && event.program.conference.end_hour
+    return unless event && start_time && event.program&.conference&.end_hour
 
     errors.add(:start_time, "can't be after the conference end hour (#{event.program.conference.end_hour})") if start_time.hour >= event.program.conference.end_hour
   end
 
   def start_before_start_hour
-    return unless event && start_time && event.program&.conference && event.program.conference.start_hour
+    return unless event && start_time && event.program&.conference&.start_hour
 
     errors.add(:start_time, "can't be before the conference start hour (#{event.program.conference.start_hour})") if start_time.hour < event.program.conference.start_hour
   end
diff --git a/app/models/room.rb b/app/models/room.rb
index 4bd88834..af180fb6 100644
--- a/app/models/room.rb
+++ b/app/models/room.rb
@@ -2,6 +2,7 @@
 
 class Room < ApplicationRecord
   include RevisionCount
+
   belongs_to :venue
   has_many :event_schedules, dependent: :destroy
   has_many :tracks
diff --git a/app/models/survey.rb b/app/models/survey.rb
index 933fa9f6..62ce553e 100644
--- a/app/models/survey.rb
+++ b/app/models/survey.rb
@@ -25,7 +25,7 @@ class Survey < ActiveRecord::Base
     now = Time.current.in_time_zone(timezone)
 
     if start_date && end_date
-      now >= start_date && now <= end_date
+      now.between?(start_date, end_date)
     elsif start_date && !end_date
       now >= start_date
     elsif !start_date && end_date
diff --git a/app/models/ticket.rb b/app/models/ticket.rb
index 677ef90f..abc014cd 100644
--- a/app/models/ticket.rb
+++ b/app/models/ticket.rb
@@ -81,7 +81,7 @@ class Ticket < ApplicationRecord
 
   def tickets_of_conference_have_same_currency
     tickets = Ticket.where(conference_id: conference_id)
-    return if tickets.count.zero? || (tickets.count == 1 && self == tickets.first)
+    return if tickets.none? || (tickets.one? && self == tickets.first)
 
     unless tickets.all?{|t| t.price_currency == price_currency }
       errors.add(:price_currency, 'is different from the existing tickets of this conference.')
diff --git a/app/models/ticket_purchase.rb b/app/models/ticket_purchase.rb
index f8e6c210..6d373d3f 100644
--- a/app/models/ticket_purchase.rb
+++ b/app/models/ticket_purchase.rb
@@ -97,8 +97,6 @@ class TicketPurchase < ApplicationRecord
   end
 end
 
-private
-
 def set_week
   self.week = created_at.strftime('%W')
   save!
diff --git a/app/models/track.rb b/app/models/track.rb
index d34bfbef..b249bef3 100644
--- a/app/models/track.rb
+++ b/app/models/track.rb
@@ -233,8 +233,8 @@ class Track < ApplicationRecord
     (program.tracks.accepted + program.tracks.confirmed - [self]).each do |existing_track|
       next unless existing_track.room == room && existing_track.start_date && existing_track.end_date
 
-      if start_date >= existing_track.start_date && start_date <= existing_track.end_date ||
-         end_date >= existing_track.start_date && end_date <= existing_track.end_date ||
+      if start_date.between?(existing_track.start_date, existing_track.end_date) ||
+         end_date.between?(existing_track.start_date, existing_track.end_date) ||
          start_date <= existing_track.start_date && end_date >= existing_track.end_date
         errors.add(:track, 'has overlapping dates with a confirmed or accepted track in the same room')
         break
diff --git a/app/models/user.rb b/app/models/user.rb
index 564384f9..4cbac281 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -30,6 +30,7 @@ class User < ApplicationRecord
                                                    :avatar_content_type, :avatar_file_size, :avatar_updated_at, :updated_at, :confirmation_sent_at, :confirmation_token, :reset_password_token]
 
   include Gravtastic
+
   gravtastic size: 32
 
   before_create :setup_role
@@ -238,7 +239,7 @@ class User < ApplicationRecord
   end
 
   def registered
-    if registrations.count == 0
+    if registrations.none?
       'None'
     else
       registrations.map { |r| r.conference.title }.join ', '
@@ -247,7 +248,7 @@ class User < ApplicationRecord
 
   def attended
     registrations_attended = registrations.where(attended: true)
-    if registrations_attended.count == 0
+    if registrations_attended.none?
       'None'
     else
       registrations_attended.map { |r| r.conference.title }.join ', '
@@ -271,7 +272,7 @@ class User < ApplicationRecord
   end
 
   def self.empty?
-    User.count == 1 && User.first.email == 'deleted@localhost.osem'
+    User.one? && User.first.email == 'deleted@localhost.osem'
   end
 
   private
diff --git a/db/migrate/20140730104658_migrate_roles_for_cancancan.rb b/db/migrate/20140730104658_migrate_roles_for_cancancan.rb
index ed76b7c0..adbe9d05 100644
--- a/db/migrate/20140730104658_migrate_roles_for_cancancan.rb
+++ b/db/migrate/20140730104658_migrate_roles_for_cancancan.rb
@@ -8,7 +8,7 @@ class MigrateRolesForCancancan < ActiveRecord::Migration
     Role.all.each do |role|
       role.users.each do |user|
         Conference.all.each do |conference|
-          if role.name == 'Admin' || role.name == 'Organizer'
+          if ['Admin', 'Organizer'].include?(role.name)
             user.add_role :organizer, conference
             user.update_columns(is_admin: true)
           else
diff --git a/db/migrate/20170531094819_move_conferences_to_organizations.rb b/db/migrate/20170531094819_move_conferences_to_organizations.rb
index 7f7e776c..01cfa87f 100644
--- a/db/migrate/20170531094819_move_conferences_to_organizations.rb
+++ b/db/migrate/20170531094819_move_conferences_to_organizations.rb
@@ -13,7 +13,7 @@ class MoveConferencesToOrganizations < ActiveRecord::Migration
     add_reference :conferences, :organization, index: true
 
     TempConference.reset_column_information
-    if TempConference.count != 0
+    if TempConference.any?
       organization = TempOrganization.create(name: 'organization', description: 'Default organization')
       TempConference.all.each do |conference|
         conference.organization_id = organization.id
diff --git a/lib/tasks/data_demo.rake b/lib/tasks/data_demo.rake
index ae57b717..0e5450b4 100644
--- a/lib/tasks/data_demo.rake
+++ b/lib/tasks/data_demo.rake
@@ -5,6 +5,7 @@ namespace :data do
 
   task demo: :environment do
     include FactoryBot::Syntax::Methods
+
     conference = create(:full_conference, title: 'Open Source Event Manager Demo', short_title: 'osemdemo' ,description: "This is a [Open Source Event Manager](http://osem.io/) demo instance. You can log in as **admin** with the password **password123** or just you just [sign up](/accounts/sign_up) with your own user. We hope you enjoy checking out all the functionality, if you have questions don't hesitate to [contact us](http://osem.io/#contact)!\r\n\r\n## Data will be destroyed every thirty minutes or whenever someone updates the [OSEM source code on github](https://github.com/openSUSE/osem/commits/master).")
     conference.contact.update(email: 'osemdemo@osem.io', sponsor_email: 'osemdemo@osem.io')
     create(:admin, email: 'admin@osem.io', username: 'admin', password: 'password123', password_confirmation: 'password123')
diff --git a/lib/tasks/events_registrations.rake b/lib/tasks/events_registrations.rake
index 171f4b25..ccab6e0c 100644
--- a/lib/tasks/events_registrations.rake
+++ b/lib/tasks/events_registrations.rake
@@ -7,13 +7,13 @@ namespace :events_registrations do
       duplicates = EventsRegistration.all.map { |er| er.id if er.valid? == false}.compact
 
       puts "Duplicates found: #{duplicates.count}"
-      if duplicates.count > 0
+      if duplicates.any?
         puts "With IDs: #{duplicates}"
       end
 
       EventsRegistration.all.each do |er|
         records = EventsRegistration.where(registration_id: er.registration_id, event_id: er.event_id)
-        if records.count > 1
+        if records.many?
           # Iterate through duplicates (excluding 1st record)
           (1..(records.count - 1)).each do |i|
             puts "Deleting EventsRegistration record with ID #{records[i].id} ..."
diff --git a/spec/mailers/mailbot_spec.rb b/spec/mailers/mailbot_spec.rb
index 39aaf3cf..afcdb0b0 100644
--- a/spec/mailers/mailbot_spec.rb
+++ b/spec/mailers/mailbot_spec.rb
@@ -32,7 +32,7 @@ describe Mailbot do
     end
 
     describe '.registration_mail' do
-      include_examples 'mailer actions' do
+      it_behaves_like 'mailer actions' do
         let(:mail) { Mailbot.registration_mail(conference, user).deliver_now }
       end
     end
@@ -44,7 +44,7 @@ describe Mailbot do
                                          accepted_body:    'Lorem ipsum dolor sit amet, consectetuer adipiscing elit')
       end
 
-      include_examples 'mailer actions' do
+      it_behaves_like 'mailer actions' do
         let(:mail) { Mailbot.acceptance_mail(event).deliver_now }
       end
     end
@@ -56,7 +56,7 @@ describe Mailbot do
                                          rejected_body:    'Lorem ipsum dolor sit amet, consectetuer adipiscing elit')
       end
 
-      include_examples 'mailer actions' do
+      it_behaves_like 'mailer actions' do
         let(:mail) { Mailbot.rejection_mail(event).deliver_now }
       end
     end
@@ -68,7 +68,7 @@ describe Mailbot do
                                          confirmed_without_registration_body:    'Lorem ipsum dolor sit amet, consectetuer adipiscing elit')
       end
 
-      include_examples 'mailer actions' do
+      it_behaves_like 'mailer actions' do
         let(:mail) { Mailbot.confirm_reminder_mail(event).deliver_now }
       end
     end
diff --git a/spec/support/login_macros.rb b/spec/support/login_macros.rb
index 7557c14d..96237512 100644
--- a/spec/support/login_macros.rb
+++ b/spec/support/login_macros.rb
@@ -2,6 +2,7 @@
 
 module LoginMacros
   include Warden::Test::Helpers
+
   Warden.test_mode!
 
   def sign_in(user)