Inform that there are no rooms in the schedule

Inform that there are no rooms when creating the schedule with a message instead of creating a room with the title "No rooms". The message also include a link to the place where rooms are created.

app/controllers/admin/schedules_controller.rb

@@ -25,7 +25,7 @@ module Admin
       @event_schedules = @schedule.event_schedules
       @unscheduled_events = @program.events.confirmed - @schedule.events
       @dates = @conference.start_date..@conference.end_date
-      @rooms = (@venue && @venue.rooms.any?) ? @venue.rooms : [Room.new(name: 'No Rooms!', size: 0)]
+      @rooms = @conference.venue.rooms if @conference.venue
     end
 
     def destroy

app/views/admin/schedules/show.html.haml

@@ -7,7 +7,8 @@
       %p.text-muted
         Create the schedules for the conference
 
-.row
+- if @rooms.present?
+  .row
     .col-md-2
       Selected schedule
       = check_box_tag @conference.short_title, @schedule.id, (@schedule.id == @selected_schedule.try(:id)),
@@ -31,6 +32,12 @@
         - @dates.each do |date|
           .tab-pane{ class: "#{ (@dates.first == date) ? 'active' : '' }", id: "#{date}" }
             = render partial: 'day_tab', locals: { date: date }
+- else
+  .h3
+    No Rooms!
+    %small
+      = link_to 'Create rooms', admin_conference_venue_rooms_path
+      before creating the schedule.
 
 :javascript
   $(document).ready( function() {