Could I get some eyes on this tiny ActiveRecord patch?

I submitted a tiny patch to ActiveRecord's
AssociationCollection#add_record_to_target_with_callbacks to fix what
I believe to be a bug in the way that AssociationCollection#<< behaves
if the :uniq option is set on its reflection.

When AssociationCollection#<< is called, it invokes
#add_record_to_target_with_callbacks, which doesn't pay any attention
to the reflection's :uniq option before pushing to the @target array.
Since :uniq only causes filtering of the result set in find_target,
this means that we end up with unexpected results in our collection if
we access it after we push duplicate records in, until the collection
gets reloaded:

Given a class, Contact, that has_and_belongs_to_many :tickets
with :uniq => true, for instance:

c = Contact.find(1)

=> #<Contact id: 1, ...>

c.tickets

=> [#<Ticket id: 1, ...>, #<Ticket id: 2, ...>, ...]

c.tickets.size

=> 6

c.tickets << Ticket.find(1)

=> [#<Ticket id: 1, ...>, #<Ticket id: 2, ...>, ...]

c.tickets.size

=> 7

c = Contact.find(1)

=> #<Contact id: 1, ...>

c.tickets.size

=> 6

Anyway, the really simple fix is at http://rails.lighthouseapp.com/projects/8994/tickets/738
-- a few sets of eyes on it would be helpful.

Thanks!