Tracks

Included in this pull request:
-tracks model link, name and user_id foreign key
-tracks will belong to a user
-normal crud tracks_controller
-change social_media_controller put#update to patch#update to follow new convention

Future thoughts:
-would like users to be able to upload their own audio files, right now i'm just assuming that its hosted on another site like soundcloud
-could implement our own audio play and funnel all music into it