Alembic does not support SQLite, and we don't recommend to use SQLite in production deployments, so migrations are rarely needed for SQLite. So we don't bother about working around SQLite limitations, and create database from models when it is in use. Of course, we still use alembic to migrate schema on 'real' databases. Change-Id: I8237a29c7bf5b60136bb1b72fd029fe9ce1abe1f