title: Rails Admin - List, Scope on association
body: <p>I have categories and articles. They have a HABTM relation. I would like the possibility of listing each category and the articles that have relation to that article in the list view of articles.</p>
  
  <p>How can I accomplish this?</p>
  
  <p>I have tried with scopes, however this require a function?</p>
  
  <p><a href="https://github.com/mathieul/rails_admin" rel="nofollow">https://github.com/mathieul/rails_admin</a></p>