Failing test for save issue with association named record

In Rails 4, when we add an association named `record`, the model is never persisted even if `save!` and `create!` does not raise and `save` and `create` return true.
This is probably due to the use of `record` method in AR code then it would useful to have a Warning / Error to prevent this odd behavior.

[UPDATE]
As this MR breaks other test I wrote a gist which demonstrate the issue : https://gist.github.com/bobbus/7137420