let vc = LoginViewController(nibName: "LoginViewController", bundle: nil)
self.navigationController?.pushViewController(vc, animated: true)
let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)
let nextViewController = storyBoard.instantiateViewController(withIdentifier: "nextView") as! NextViewController
self.present(nextViewController, animated:true, completion:nil)