title: Upload a WAV file with Paperclip and store both .wav and .mp3 versions
body: <p>I have a Rails application where people can use an in browser sound editor to create wav files and upload them to the server.</p>
  
  <p>I use Paperclip for handling the sound file upload.</p>
  
  <p>I would like to be able to convert the wav file to an mp3, but keep both files.</p>
  
  <p>I have read about Paperclip processors, but I'm not sure how to use them to get both files instead of just converting to mp3 only.</p>