title: ActiveAdmin - Index as grid - multiple field
body: <p>I have a picture model with attributes 'img' and 'caption'</p>
  
  <p>I rendered the images using index as grid</p>
  
  <pre><code>index as: :grid, columns: 2 do |pic|
    link_to image_tag(pic.image), admin_pic_path(pic)
  end
  </code></pre>
  
  <p>This renders all the images without any problem. I also want caption along with the images so that i have a heading for each image. 
  Anyone knows how to solve this ?Is it possible to render multiple fields using index as grid ?</p>