3 Shrink the web

Added shrinktheweb API for screenshots because it's free (tossing cloudinary)
```ruby
class Site
  def formatted_url
    url =~ /\Ahttp:\/\//\ ? url : "http://#{@site.url}"
  end
end
```

```html
<%= link_to @site.url, @site.formatted_url %> 
```