Fixing an issue where group singletons lose other class fields

src/command_system/database.py

@@ -39,6 +39,6 @@ def as_group_singleton(cls):
 
     return type(
         cls.__name__,
-        (ModelBase,),
+        (ModelBase, cls),
         dict(**columns, get_or_create=classmethod(get_or_create_standin))
     )