RFR ---- Added matchup associations, review, views, and mo, and mo and mo!

You can combine your validations on a single attribute like so:

```ruby
  validates :body,
    presence: {:message => "The opinion can't be empty!"},
    uniqueness: {:message => "That opinion already exists!"}
```

Also you should validate the presence of `winner`, not `winner_id`:
```ruby
  validates :winner, presence: {:message => "You must vote!"}
```