Changing indentation for case in Emacs (ruby.el)

Using Emacs to edit ruby files, I’d like to have case expresssions
indented
thus:

case x
when p then s
when q then t
end

rather than:

case x
when p then s
when q then t
end

Can I do this easily?

(PS: The 1st edition of Programming Ruby seems to use the first form,
judging from the on-line version; the 2nd edition uses the 2nd form,
looking at the paper copy of the book.)

  • Will