Membership requires login

app/helpers/activities_helper.rb

@@ -1,5 +1,6 @@
 module ActivitiesHelper
   def require_organizer!
+    require_login!
     if !@activity.may_change?(current_person)
       flash_message(:danger, I18n.t('authentication.organizer_required'))
       redirect_to group_activity_path(@group, @activity)