Composite primary keys

Hello,

Is it true that Rails doesn’t support composite primary keys? I have a
legacy system and was pondering adding a new interface to it. This whole
Rails thing (and yes, Ruby too) seems pretty interesting but I’d feel
ashamed of myself adding an additional column called ‘id’ when there’s
already a perfectly good composite key.

Assuming the rumors are true, is there any work being done in this area?

Thanks,
John