Add vote functionality to tracks

app/models/vote.rb

@@ -2,7 +2,7 @@
 
 class Vote < ApplicationRecord
   belongs_to :user
-  belongs_to :event
+  belongs_to :votable, polymorphic: true
 
   has_paper_trail ignore: [:updated_at], meta: { conference_id: :conference_id }
 
@@ -11,6 +11,6 @@ class Vote < ApplicationRecord
   private
 
   def conference_id
-    event.program.conference_id
+    votable.program.conference_id
   end
 end