title: Versioning an app retrospectively
body: <p>I've recently started working on an app project that's a couple of years old.  They want to start doing code releases and versioning just to record all the changes after each iteration.</p>
  
  <p>Is there an efficient way to figure out what the current version should be?  There are approx 5000 commits in the current master that I'm guessing I'll just have to rake through.</p>