func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

        // Ask user for Notification permission
        registerNotification() {(allowed) -> Void in
            if allowed {
                UIApplication.shared.registerForRemoteNotifications()
            }
        }
        return true
    }

    func registerNotification(completion: @escaping (_ allowed: Bool) -> Void) {
        UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound, .badge]) {
            (granted, error) in
            print("Permission granted: \(granted)")

            // Get setting to check answer from User
            UNUserNotificationCenter.current().getNotificationSettings { (settings) in
                print("Notification settings: \(settings)")
                guard settings.authorizationStatus == .authorized else {
                    completion(false)
                    return
                }
            }
            completion(true)
        }
    }

    func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
        let tokenParts = deviceToken.map { data -> String in
            return String(format: "%02.2hhx", data)
        }
        let token = tokenParts.joined()
        print("Device Token: \(token)")
    }

    func application(_ application: UIApplication, didFailToRegisterForRemoteNotificationsWithError error: Error) {
        print("Failed to register: \(error)")
    }