         grid.addChild(scoreNode)
     }
     
+    private func initResignActiveNotificationObserver() {
+        NSNotificationCenter.defaultCenter()
+            .addObserver(self, selector: #selector(self.pauseButtonTouched),
+                         name: UIApplicationWillResignActiveNotification, object: nil)
+    }
     
     // ==============================================
     // MARK: Methods to create custom sprite nodes

        initCountdownTimer()
        initPauseButton()
        initScore()
        
        // Set game to 30FPS
        view.frameInterval = 2

// MARK: PauseMenuDelegate
extension GameScene: PauseMenuDelegate {
    func pauseMenuDismissed() {
        hasGameStarted = false
        isGamePaused = false
        if countdownNode.parent == nil {
            grid.addChild(countdownNode)
        }
        if !gameState.isMultiplayer {
            countdownNode.start()
        }
        addGestureRecognizers()
    }
    
    func leaveGameSelected() {
        logicEngine.stopTick()
        if gameState.isMultiplayer {
            GameNetworkPortal._instance.disconnectFromRoom()
        }
        NSNotificationCenter.defaultCenter().postNotificationName("exitGame", object: nil)
    }
}