Model namespec breaks the @response tag.

For some weird reason this is not working:

```ruby
    # @response Success(201) [Hash{url: RailsUrlShortener::Url}]
```

But something like this works:

```ruby
    # @response Success(201) [Hash{url: User}]
```

Or even strange, this works too, using the same class:

```ruby
    # @response List of Urls(200) [Array<RailsUrlShortener::Url>]
```