title: How to add subview to UIViewController pushing UINavigationBar behind
body: <p>What I want is as follows:</p>
  
  <p>Basically I have a view controller with navigation bar. There is a menu button as left UINavigationBarItem. On click of menu button list of menu items will animate from top. This is achieved using 'addSubview' method. But menu list is added as subview below navigation bar. I want to add menu list view pushing navigation bar behind menu list view. I dont want to hide navigation bar.</p>
  
  <p>Thanks</p>