Do not use JS to initialize the schedule

- Only use JS for the drag&drop functionality and to the set/alter the time and rooms of the EventSchedule object.

- Introduce has_many :events, through: :event_schedules association to get unscheduled event easily

app/models/schedule.rb

@@ -1,4 +1,5 @@
 class Schedule < ActiveRecord::Base
   belongs_to :program
   has_many :event_schedules, dependent: :destroy
+  has_many :events, through: :event_schedules
 end