Introduce an association to Events from Conferences

app/models/conference.rb

@@ -10,6 +10,8 @@ class Conference < ActiveRecord::Base
 
   has_many :tracks
   has_many :halls
+  has_many :events, through: :tracks
+
 
   accepts_nested_attributes_for :tracks, :halls, reject_if: :all_blank, allow_destroy: true
 

app/models/track.rb

@@ -1,5 +1,8 @@
 class Track < ActiveRecord::Base
+  include PropositionAccepting
+
   belongs_to :conference
+  has_many :events, through: :propositions, source: :proposable, source_type: Event
 
   validates :name, presence: true
   validates :color, presence: true, format: {with: /\A#?[a-f0-9]{6}\z/i}