(Inspired by https://github.com/yyjhao/html5-hearts) Wiki: https://en.wikipedia.org/wiki/Hearts_(card_game) * Using Redux-Saga to easily handle side effects like websocket. * Three mode: ---- Play mode: user can using this app to play with other client. ---- Watch mode: user can watch current playing game. ---- Replay mode: user can replay game history by JSON log. * Because of immutable data structure, it allow players to undo/redo game history whenever you want!