title: Tap tab bar to scroll to top of UITableViewController
body: <p>Tapping the tab bar icon for the current navigation controller already returns the user to the root view, but if they are scrolled way down, if they tap it again I want it to scroll to the top (same effect as tapping the status bar). How would I do this? </p>
  
  <p>A good example is Instagram's feed, scroll down then tap the home icon in the tab bar to scroll back to top.</p>
  
  <p>The scrolling back to the top is easy, but connecting it to the tab bar controller is what I'm stuck on.</p>