[chef] renaming a role

[Chris Burroughs < >]

We have a bunch of roles called foo-abc-123 that we would like to rename 
bar-abc-123.  I've done several naive searches like on how to rename or 
change role names without finding anything.

Obviously for local purposes I can do git mv && unload-new-name, but 
that would leave all of the nodes with $OLD_NAME in a lurch.

Ideally I'd like to find some sort of integrated rename mechanism. 
Lacking that I think my question becomes: How do I change the run lists 
of all nodes with role[foo] to role[bar] without changing anything else 
about the run list?