adds user un/follow functionality
adds likes model and functionality
adds play model to track song play count. READ NOTES FOR ERROR DETAILS

AN ERROR OCCURED DURING MIGRATION OF THE PLAYS TABLE. Currently there is no migration for a plays model, but somehow it still makes the table. If problems occur in the future, refer to the migration for the play table in the comments of the play model
adds user playlist playback history
adds saved playlist functionality and views