Sort events by time,room on the linear schedule

app/models/event_schedule.rb

@@ -41,6 +41,13 @@ class EventSchedule < ApplicationRecord
     start_time + event.event_type.length.minutes
   end
 
+  ##
+  # Returns a time + room number string for sorting.
+  #
+  def sortable_timestamp
+    "#{start_time.to_i}-#{room&.order}"
+  end
+
   ##
   # Returns event schedules that are scheduled in the same room and start_time as event
   #