Add method for retrieving games by id.
Implement RestfulAPI.game(long).
Implement RestfulAPI.createPlayer().
Implement RestfulAPI.updatePlayer(long).
Implement RestfulAPI.deletePlayer(long).
Implement RestfulAPI.createGame().
Extract a method for updating game information in Game.java.
Implement RestfulAPI.updateGame(long).
Implement RestfulAPI.deleteGame().