Correct admin for ref inv

submissions/admin.py

@@ -33,7 +33,7 @@ class RefereeInvitationAdmin(admin.ModelAdmin):
     search_fields = ['submission__title', 'submission__author_list',
                      'referee__user__last_name',
                      'first_name', 'last_name', 'email_address']
-    list_display = ('referee', submission_short_title, 'accepted', )
+    list_display = ('__str__', 'accepted', )
     list_filter = ('accepted', 'fulfilled', 'cancelled',)
     date_hierarchy = 'date_invited'