How to change background color with Sprite Kit

I am trying to create a game with Sprite Kit in Swift, but I have a little background color problem.

I started a new project in Xcode and chose the Game Presets and Sprite Kit. So I have a starter project with a gray background with "Hello World" in white and spaceships that pop up when I click on the screen.

So, I removed all the code that I'm not interested in, but when I start the game, I still have the gray background even if I try to change it in the GameScene.swift file.

Here are my files:

AppDelegate.swift

import UIKit

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate
{

var window: UIWindow?


func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
    // Override point for customization after application launch.
    return true
  }

func applicationWillResignActive(application: UIApplication) {
    // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
    // Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
  }

func applicationDidEnterBackground(application: UIApplication) {
    // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.
    // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
  }

func applicationWillEnterForeground(application: UIApplication) {
    // Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
  }

func applicationDidBecomeActive(application: UIApplication) {
    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
  }

func applicationWillTerminate(application: UIApplication) {
    // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
  }

}

      

        
        
        
      

    

GameScene.swift

import SpriteKit

class GameScene: SKScene
{
  override func didMoveToView(view: SKView)
  {
    self.backgroundColor = SKColor.whiteColor()
  }

  override func update(currentTime: CFTimeInterval)
  {
    /* Called before each frame is rendered */
  }
}

      

        
        
        
      

    

GameViwController.swift

import UIKit
import SpriteKit


class GameViewController: UIViewController
{

  override func viewDidLoad()
  {
    super.viewDidLoad()
  }

  override func prefersStatusBarHidden() -> Bool
  {
    return true
  }
}

      

        
        
        
      

    

So how do you set the background to white?