Rename user.repository to user.user_repository
Create the SpotifyTrack class and repository
Create the LastfmTrack class and repository

Ensure LastfmTrack urls are unique in the db
Add get_model methods to track repositories
Access connections directly from the connection view

Don't use the user classes
Create middleware for connection status
Fix missing session key on startup

Sessions don't have a key until they've been saved
Test lastfm connection views
Test spotify connection views