route to conference#show for custom domain

app/controllers/conferences_controller.rb

@@ -9,10 +9,17 @@ class ConferencesController < ApplicationController
     @antiquated = @conferences - @current
   end
 
-  def show; end
+  def show
+    # have to change "localhost" to ENV['OSEM_HOSTNAME'] in production 
+    check_custom_domain if request.host != 'localhost'
+  end
 
   private
 
+  def check_custom_domain
+    @conference = @conference.custom_domain.present? ? Conference.find_by(custom_domain: request.domain) : @conference
+  end
+
   def respond_to_options
     respond_to do |format|
       format.html { head :ok }

config/initializers/domain_constraint.rb

@@ -0,0 +1,6 @@
+class DomainConstraint
+  def self.matches?(request)
+  	@domains = Conference.pluck(:custom_domain).compact
+    @domains.include?(request.domain)
+  end
+end

config/routes.rb

@@ -1,5 +1,9 @@
 Osem::Application.routes.draw do
 
+  constraints DomainConstraint do
+    get '/', to: 'conferences#show'
+  end
+
   if ENV['OSEM_ICHAIN_ENABLED'] == 'true'
     devise_for :users, controllers: { registrations: :registrations }
   else

db/migrate/20170721184810_add_custom_domain_to_conferences.rb

@@ -0,0 +1,5 @@
+class AddCustomDomainToConferences < ActiveRecord::Migration
+  def change
+    add_column :conferences, :custom_domain, :string
+  end
+end

db/schema.rb

@@ -11,10 +11,10 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20170721001700) do
+ActiveRecord::Schema.define(version: 20170721184810) do
 
   create_table "ahoy_events", force: :cascade do |t|
-    t.integer  "visit_id"
+    t.uuid     "visit_id",   limit: 16
     t.integer  "user_id"
     t.string   "name"
     t.text     "properties"
@@ -127,6 +127,7 @@ ActiveRecord::Schema.define(version: 20170721001700) do
     t.integer  "end_hour",           default: 20
     t.integer  "organization_id"
     t.integer  "ticket_layout",      default: 0
+    t.string   "custom_domain"
   end
 
   add_index "conferences", ["organization_id"], name: "index_conferences_on_organization_id"