Added functionality to vote on Goal and Efficiency
Added new Endpoints:
PUT /api/meetings/:id/vote/goal/up
PUT /api/meetings/:id/vote/goal/down
PUT /api/meetings/:id/vote/efficiency/up
PUT /api/meetings/:id/vote/efficiency/down
GET /api/leaderboard/leaderBoard/goal
GET /api/leaderboard/leaderBoard/efficiency

Close #11
Merge branch 'master' of github.com:meip/bettermeeting
Added mongodb.uri for Heroku Use