implement and add tests for POST /follow controller
implement and add tests for POST /listen controller
implement the music recommendation engine
Merge branch 'feature/controllers'
Merge branch 'feature/music-recommendation-engine'
Fix comment in listen routes
Add status to error returned
Implement and add tests for music recommendation controller
modify the populate music list to return an array of music ID instead of music objects
Merge branch 'feature/music-recommendation-engine'
modify user schema by making genre name for music genres listened to be the _id