Add review votes test

Added tests for user upvoting/downvoting review
You don't need these. You can login as a user would at the start of each test:

```ruby
user = FactoryGirl.create(:user)

visit new_user_session_path

fill_in 'Email', with: user.email
fill_in 'Password', with: user.password

click_button 'Sign in'
```