Play one game for multiple users

Background: 
Link to #22
When multiple players log into one game, they can take turns to judge & play.

### Given we have two players playing the game
![screen shot 2014-07-26 at 7 32 15 am](https://cloud.githubusercontent.com/assets/806135/3711111/0f19c452-14c1-11e4-9ee7-b5f15695622d.png) 

### The judge should have a blank board, players should see their own cards
![screen shot 2014-07-26 at 7 32 24 am](https://cloud.githubusercontent.com/assets/806135/3711112/28df9bfa-14c1-11e4-8c4c-9eebc43de8ee.png)

### The players select cards to play, which display on the judge's board
![screen shot 2014-07-26 at 7 32 34 am](https://cloud.githubusercontent.com/assets/806135/3711113/4d479844-14c1-11e4-88c2-c1b238bb9c49.png)

### The judge chooses the winning card, the score added to the winning player; judge's role is switched
![screen shot 2014-07-26 at 7 32 42 am](https://cloud.githubusercontent.com/assets/806135/3711114/643f463c-14c1-11e4-964f-22c1cd580efe.png)

### At the end of game, display scores for all players
![screen shot 2014-07-26 at 7 33 16 am](https://cloud.githubusercontent.com/assets/806135/3711116/70ec9f60-14c1-11e4-8fe6-4b6a6ae3301c.png)