Rooms belong to venue

app/models/venue.rb

@@ -1,9 +1,10 @@
 class Venue < ActiveRecord::Base
   belongs_to :conference
-  has_many :lodgings
+  has_many :rooms, dependent: :destroy
   before_create :generate_guid
 
   validates :name, :street, :city, :country, presence: true
+  validates :conference_id, presence: true, uniqueness: true
 
   has_attached_file :photo,
                     styles: { thumb: '100x100>', large: '300x300>' }
@@ -11,8 +12,6 @@ class Venue < ActiveRecord::Base
                                     content_type: [/jpg/, /jpeg/, /png/, /gif/],
                                     size: { in: 0..500.kilobytes }
 
-  accepts_nested_attributes_for :lodgings, allow_destroy: true
-
   after_update :send_mail_notification
 
   def address