Fix songs controller #upvote and #downvote actions and tests
-Code from last commit turned out to not be working
Add song model methods to move logic out of controller
refactor vote model methods for upvote/downvote
-refactor song controller #upvote, #downvote
Merge pull request #7 from girb0t/song_model

Fix song controller upvote/downvote actions and tests
Merge pull request #8 from girb0t/vote_model

Add vote model methods. Refactor #upvote, #downvote in Song Controller
resolve minor merge conflict
minor merge conflict resolve