Set page title

If you'd like to override the page titles, follow this pattern (from #184)

ActiveAdmin.register Post do
  # DO THIS
  show :title => :my_title_method do
    # ...
  end
  # OR THIS
  show :title => proc{ post.title } do
     # ...
  end
  # Custom actions
  collection_action :comments, :title => "My Awesome Comments" do
    # do stuff
  end
end