title: Push view controller in navigation controller with interactive transition
body: <p>I have a view at the bottom of my view controller. How can I set up an interactive transition such that as I drag the view up vertically (perhaps using <code>UIPanGestureRecognizer</code>), another view controller is pushed up?</p>
  
  <p>Similar to the default navigation controller behaviour with swiping left and right to push/pop, except this would be vertical.</p>