title: ActiveAdmin limit records on Index page
body: <p>I have some 10,000+ records in my model. In active_admin index page for that model I have set <code>config.paginate = false</code>. So all the 10,000+ records are shown by default.</p>
  
  <p>How can I limit the number to say last 500 records. I have tried using the below method described <a href="http://www.activeadmin.info/docs/2-resource-customization.html#customizing_resource_retrieval" rel="nofollow">here</a>, but its not doing anything to the index page.</p>
  
  <pre><code>ActiveAdmin.register Post do
    controller do
      def scoped_collection
        Post.all.limit(500)
      end
    end
  end
  </code></pre>