Ruby on Rails

Several times I found myself of need of a method that tells whether an ActiveRecord instance has just been created. For example, when writing generic activity logging code that needs to know whether model is newly created as opposed to updated, but the invocation is in a service outside of the model itself and thus I can't just write `after_create` and `after_update` hooks, except perhaps just to set custom flags for the service to inspect.

It's not the same as `new_record?` because `new_record?` is only true before record is saved, not after save. I'm thinking `newly_created?` or `just_created?` name. Calling it `created?` would be too ambiguous and higher chance to clash with similarly named method by application developers in their own code.

Essentially `new_record?` to `newly_created?` is the same as `marked_for_destruction?` is to `destroyed?`, or as `changes` is to `previous_changes`.

In my app I've implemented the code like this: