gistfile1.txt

func whateverMethodThisIs() {
    let defaults = NSUserDefaults.standardUserDefaults()
    self.window = UIWindow(frame: UIScreen.mainScreen().bounds)
    let mainStoryboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)

    if !defaults.boolForKey("hasDisplayedIntroduction") {
        self.window?.rootViewController = mainStoryboard.instantiateViewControllerWithIdentifier("IntroductionViewController") as! IntroductionViewController
    } else {
        self.window?.rootViewController = mainStoryboard.instantiateViewControllerWithIdentifier("SecondViewController") as! SecondViewController
    } 
    
    self.window?.makeKeyAndVisible()
}

@IBAction func button(sender: AnyObject)  {
    let defaults = NSUserDefaults.standardUserDefaults()
    defaults.setBool(true, forKey: "hasDisplayedIntroduction")
}