Redmine

I have a rather strange request from a Customer and am wondering if there is already a patch for this somewhere (since I suck at Ruby).

The basic Idea is that the category a ticket is in determines it's Priority. I can hide the Priority from the form so users can't set that. But I somehow need to assign the priority based on what category is selected.

It would require extending either the data-model, or hacking directly into issues.rb with some before_create method and a switch statement on my categories.

Is there an existing patch out there for this? Because I am tempted to simply hack this into issue before_create, but then I'd had to make sure it only runs on this one project etc..