diff --git a/rhodecode/model/users_group.py b/rhodecode/model/users_group.py
--- a/rhodecode/model/users_group.py
+++ b/rhodecode/model/users_group.py
@@ -37,6 +37,8 @@ log = logging.getLogger(__name__)
 
 class UsersGroupModel(BaseModel):
 
+    cls = UsersGroup
+
     def __get_users_group(self, users_group):
         return self._get_instance(UsersGroup, users_group,
                                   callback=UsersGroup.get_by_group_name)