- Update the migrations tool to verify migrations work up and down for both MySQL and PostgresSQL.

- Add migrations for the squashed image tables and for backfilling the uncompressed sizes
- Make sure gzip stream uses a max length when determining the uncompressed size

data/database.py

@@ -168,7 +168,7 @@ class Visibility(BaseModel):
 
 
 class Repository(BaseModel):
-  namespace_user = ForeignKeyField(User)
+  namespace_user = ForeignKeyField(User, null=True)
   name = CharField()
   visibility = ForeignKeyField(Visibility)
   description = TextField(null=True)