title: Save changes when tapping Back - Swift
body: <p>I have a Master Detail storyboard set up with a Navigation Controller. The Master view being a UITableView that shows a list of things saved using Core Data. When a row is tapped, it segues to a Detail view which has a UITextView where you can edit the data.  </p>
  
  <p>How can I call a function (or what exiting functions are available) that I can use to automatically save the changes when the User taps "Back" in the Navigation Bar?</p>