update

app/controllers/api/v1/tracks_controller.rb

@@ -1,15 +1,12 @@
 module Api
   module V1
     class TracksController < Api::BaseController
+      load_resource :conference, find_by: :short_title
       respond_to :json
 
       def index
-        if params[:conference_id].blank?
-          tracks = Track.all
-        else
-          tracks = Track.joins(:conference)
-          tracks = tracks.where(conferences: { guid: params[:conference_id] })
-        end
+        @conference ? (tracks = @conference.tracks) : (tracks = Track.all)
+
         respond_with tracks
       end
     end