7 - Vote on a review

[hchood]

As an authenticated user I want the ability to up or down vote a review So I can weed out unhelpful reviews

• For each review on a gem’s page, there is a upvote or a downvote button:
• If I have not yet voted on the review, there is both an up and a downvote button
• If I upvoted the review, there is a downvote button only
• If I downvoted the review, there is an upvote button only
• Clicking on a voting button will add one to the tally without refreshing the page
• I cannot record more than one vote for a given review