Downgrade the database

def db_downgrade(version):
    """Downgrade the database"""
    v1 = get_db_version()
    migrate_api.downgrade(url=db_url, repository=db_repo, version=version)
    v2 = get_db_version()

    if v1 == v2:
        print 'No changes made.'
    else:
        print 'Downgraded: %s ... %s' % (v1, v2)