Giving more structure to the admin tree

list of years which expand into months).
And since I was inspired:

Looks something like:

Basically, it gives a hook for pages to return their children
in a manner fit for the admin interface. In this case, instead
of returning an actual page, the ArchivePage returns dummy
pages that in turn return parts of the child list.

Code is a little more awkward than I’d like (mainly just in
archive_page.rb, the rest is pretty clean), but it works.

Doesn’t lead itself to extension bundling as it needs to make
a change to one of the js files.

I was thinking maybe that tree_children and tree_child(slug)
might be a more appropriate way of performing find_by_url -
in that way the tree that you see in the admin interface has
a 1:1 relationship with each part of the slug.