Look into using callbacks, e.g. after_create or before_create (define the methods and they get fired as you'd expect)
You could check for the presence of the category id in such a callback, and then do your key stuff.
Look into using callbacks, e.g. after_create or before_create (define the methods and they get fired as you'd expect)
You could check for the presence of the category id in such a callback, and then do your key stuff.