title: Convert durations in Ruby - hh:mm:ss.sss to milliseconds and vice versa
body: <p>I was wondering if there is a built-in method in Ruby that allows me to convert lap times in the format of hh:mm:ss.sss to milliseconds and vice versa.
  Since I need to do some calculations with it, I assumed that converting to milliseconds would be the easiest way to do this. Tell me if I am wrong here :)</p>