Refactor controllers

app/controllers/api/tracks_controller.rb

@@ -1,10 +1,18 @@
 module API
   class TracksController < ApplicationController
+    before_action :set_track, only: :show
+
     def index
       @tracks = Track.all
     end
 
     def show
+    end
+
+
+    private
+
+    def set_track
       @track = Track.find(params[:id])
     end
   end