fix

settings/forms.py

@@ -83,8 +83,7 @@ class MainPageThemes(forms.Form):
         attributes = {'exposition_themes': 'main_page_expo', 'conference_themes': 'main_page_conf'}
         for obj_list in attributes.keys():
             for i, obj in enumerate(data[obj_list], 1):
-                setattr(obj, attributes[obj_list], i)
-                obj.save()
+                obj.__class__.objects.filter(pk=obj.pk).update(**{attributes[obj_list]: i})
 
 
 class MainPageNews(forms.Form):