mongoid/mongoid — pull request #1831 by ono (2012-03-16 22:45:55+00:00)
Title: Allowing specifying type on find_or_(initialize|create)_by for associations

We discussed this on #1817. This pull request allows you to specify a subclass of the association model on find_or_create_by.

e.g.

```ruby
firefox.shapes.find_or_create_by({ x: 0, y: 0 }, Rectangle)
```