title: display one-to-many relationship for a model in Django admin (list mode)
body: <p>In Django admin site, when listing all the objects for a given model, I know we can customize which columns get displayed for a ModelA via <code>list_display</code></p>
  
  <p>Say that ModelA has a one-to-many relationship with ModelB. I would like to add another column on the listing page for ModelA, where each entry is a URL pointing to all objects of ModelB having a foreign key relationship on corresponding instance of Model A in that row. How can I achieve this customization with the admin app?</p>