Using a module to share common association logic in Rails

UPDATE:  If I did this again, I would consider packaging the code as a Concern

I recently wanted to DRY up some repetitive Rails association code, similar associations used in multiple models.  This gave me the opportunity to figure out a few tricks, like creating a module Class method and using metaprogramming to add dynamically named accessors.

Anyway, here is the Module:

...and the client model...