Add a menu entry for a collection action

You defined a custom collection action for a resource like this:

ActiveAdmin.register Article do
  collection_action :stats do
    # stats stuff
  end
end

And now you want to add a menu entry for that page. To do so you need to use the action_item.

ActiveAdmin.register Article do
  action_item { link_to "Stats", stats_admin_articles_path }

  collection_action :stats do
    # stats stuff
  end
end

Warning: This works only for collection actions and adding member actions links should be done in the index page or any page but not in the menu.