I'll been searching this for a while and I can't find nothing about it.
After the latest update, Rhythmbox (which was my main mp3 player on my Ubuntu Latest distro) stopped functioning: it dies just after startup. So, I turned to Clementine which I like a lot. However in Rhythmbox I had my playlists and ratings.
This simple tutorial will explain how to install Clementine and Rhythmbox scopes for Unity music lens.