Show missing speakers in reports

app/controllers/admin/events_controller.rb

@@ -144,6 +144,10 @@ module Admin
       @events_commercials = Commercial.where(commercialable_type: 'Event', commercialable_id: @events.pluck(:id))
       @events_missing_commercial = @events.where.not(id: @events_commercials.pluck(:commercialable_id))
       @events_with_requirements = @events.where.not(description: ['', nil])
+
+      attended_registrants_ids = @conference.registrations.where(attended: true).pluck(:user_id)
+      @missing_event_speakers = EventUser.joins(:event).where('event_role = ? and program_id = ?', 'submitter', @program.id).
+                                                                                        where.not(user_id: attended_registrants_ids).includes(:user, :event)
     end
 
     private