Hide Join Games when no games to join.

src/components/create-or-join/CreateOrJoin.jsx

@@ -29,9 +29,11 @@ class CreateOrJoin extends React.Component {
               <Button size='large' className='shadow' onClick={this.props.showNewGame}>
                 New Game
               </Button>
+              {this.props.start.start.games.length > 0 ? (
                   <Button size='large' className='shadow' onClick={this.props.showJoinGame}>
                     Join Game
                   </Button>
+              ) : (<Fragment />)}
             </Fragment>
         );
     }