title: Rails rabl - returning ALL attributes, not just named ones
body: <p>Rabl allows you to grab the attributes by naming them in your view, for instance:</p>
  
  <pre><code>object @user
  attributes :name, :email
  </code></pre>
  
  <p>I have a model whose attributes are will not be known, but I'd like to display everything returned from the controller in my instance variable using rabl.</p>
  
  <p>Is there a shortcut like:</p>
  
  <pre><code>attributes :all
  </code></pre>
  
  <p>etc.</p>
  
  <p>Thanks</p>