Add details of proposal in show page

app/views/proposal/show.html.haml

@@ -16,6 +16,12 @@
     %dl
       %dt Date:
       %dd= @event.start_time.strftime("%Y %B %e %H:%M") if @event.start_time
+      %dt Duration:
+      %dd= show_time(@event.event_type.length)
+      %dt Room:
+      %dd
+        - if @event.room_id
+          = @event.room.name
       %dt Conference:
       %dd= @event.conference.title
       %dt Language:
@@ -25,6 +31,11 @@
         - if @event.track_id
           %span.label{:style =>"background-color: #{@event.track.color};"}
             = @event.track.name
+      %dt Difficulty:
+      %dd
+        - if @event.difficulty_level_id
+          %span.label{:style =>"background-color: #{@event.difficulty_level.color};"}
+            = @event.difficulty_level.title
   .col-md-9
     .row
       .col-md-12