Fix alembic migrations importing app

Ensure we connect to loaded config db

config_app/config_endpoints/api/suconfig_models_pre_oci.py

@@ -4,6 +4,8 @@ from config_app.config_endpoints.api.suconfig_models_interface import SuperuserC
 
 
 class PreOCIModel(SuperuserConfigDataInterface):
+    # Note: this method is different than has_users: the user select will throw if the user
+    # table does not exist, whereas has_users assumes the table is valid
     def is_valid(self):
         try:
             list(User.select().limit(1))