The playground is now available at http://play.sqlflow.org. It is hosted on the Google Cloud Platform. Please link it at the homepage. <img width="1155" alt="Screen Shot 2019-07-15 at 11 52 46 AM" src="https://user-images.githubusercontent.com/29932814/61240984-60a3ef00-a6f7-11e9-83b5-d4ed924686d1.png">