Ran into an interesting case last night, and I was hoping that someone
on the list here could give me some guidance.
I've got a Polymorphic association for Addresses (which can belong to
two different models).
The catch is, one model requires a strict, precise address, and the
other only requires a City, State and Postal Code.
I want to use :validates_presence_of :street, :city, :state, and
:postal_code, but only if the instance is being assigned to the model
requiring stricter address validation.