code: function( userId ) {
  		return this.memory.getPublicRoom()
  		.then(function( roomId ) {
  			if ( roomId ) {
  				return this.enter( userId, roomId);
  			} else {
  				return promise.reject( 'Could not find a public room' );
  			}
  		}.bind(this));
  	}
docs: Join an available public room or create one
  
  @param  {String} userId id of the user whose entering a room
  @return {Promise} This promise will resolve by sending a room instance, or reject if no public rooms available