I've populated the data, where available, from the field "Number of
current members The number of full members (owners) in the co-op." in
the wordpress admin.
I ran `ruby migrate_coop_pages.rb` in `scripts`. There will need to be
some manual tidying up of the generated `.md` files under `_coops` but
I think this is a good start. As a one-off it doesn't warrant the time
it would take to improve the migration script.
