add relationships for booths

app/models/booth.rb

@@ -1,2 +1,7 @@
 class Booth < ActiveRecord::Base
+  belongs_to :conference
+  has_many :booth_requests
+  has_many :users, through: :booth_requests
+
+  validate :title, presence: true
 end

app/models/booth_request.rb

@@ -0,0 +1,4 @@
+class BoothRequest < ActiveRecord::Base
+  belongs_to :booth
+  belongs_to :user
+end

app/models/conference.rb

@@ -22,6 +22,7 @@ class Conference < ActiveRecord::Base
   has_many :supporters, through: :ticket_purchases, source: :user
   has_many :tickets, dependent: :destroy
   has_many :resources, dependent: :destroy
+  has_many :booths,  dependent: :destroy  
 
   has_many :lodgings, dependent: :destroy
   has_many :registrations, dependent: :destroy

app/models/user.rb

@@ -50,11 +50,13 @@ class User < ActiveRecord::Base
   has_many :votes, dependent: :destroy
   has_many :voted_events, through: :votes, source: :events
   has_many :subscriptions, dependent: :destroy
+  has_many :booth_requests
+  has_many :booths, through: :users_booths
   accepts_nested_attributes_for :roles
 
   scope :admin, -> { where(is_admin: true) }
   scope :active, -> { where(is_disabled: false) }
-
+  
   validates :email, presence: true
 
   validates :username,