get upgrade working on sqlite with foreign key naming convention

jupyterhub/orm.py

@@ -16,12 +16,12 @@ from sqlalchemy import Boolean
 from sqlalchemy import Column
 from sqlalchemy import create_engine
 from sqlalchemy import DateTime
-from sqlalchemy import Enum
 from sqlalchemy import event
 from sqlalchemy import exc
 from sqlalchemy import ForeignKey
 from sqlalchemy import inspect
 from sqlalchemy import Integer
+from sqlalchemy import MetaData
 from sqlalchemy import or_
 from sqlalchemy import select
 from sqlalchemy import Table
@@ -115,7 +115,17 @@ class JSONList(JSONDict):
         return value
 
 
-Base = declarative_base()
+meta = MetaData(
+    naming_convention={
+        "ix": "ix_%(column_0_label)s",
+        "uq": "uq_%(table_name)s_%(column_0_name)s",
+        "ck": "ck_%(table_name)s_%(constraint_name)s",
+        "fk": "fk_%(table_name)s_%(column_0_name)s_%(referred_table_name)s",
+        "pk": "pk_%(table_name)s",
+    }
+)
+
+Base = declarative_base(metadata=meta)
 Base.log = app_log