title: Push notification does not work in swift 3.0
body: <p>Initial we import the <code>UserNotifications</code> framework 
  and we initialize the delegate method in <code>AppDelegate.swift</code> class</p>
  
  <pre><code>if #available(iOS 10.0, *){
  
          UNUserNotificationCenter.current().delegate = self
          let center = UNUserNotificationCenter.current()
          center.requestAuthorization(options:[.badge, .alert, .sound]) { (granted, error) in
              if (granted)
              {
                  UIApplication.shared.registerForRemoteNotifications()
              }
              else{
                  //Do stuff if unsuccessful...
              }
              // Enable or disable features based on authorization.
          }
  
      }
  </code></pre>