OpenStack Study: migration.py

**** CubicPower OpenStack Study ****

def db_sync(version=None, init_version=0):

    """Migrate the database to `version` or the most recent version."""

    return IMPL.db_sync(engine=db_api.get_engine(),

                        abs_path=MIGRATE_REPO_PATH,

                        version=version,

                        init_version=init_version)