[feat]Add valid date range to fullcalendar

app/views/schedules/vertical_schedule.haml

@@ -8,4 +8,6 @@
   #vert-schedule-full-calendar
   #fullcalendar{ data: { rooms: @rooms, events: @event_schedules, day: @day,
   'start-hour': @conference.start_hour, 'end-hour': @conference.end_hour,
+  'start-date': @conference.start_date,
+  'end-date': @conference.end_date + 1.day,
   'scheduler-license-key': @scheduler_license_key } }