Feature proposal: Silently skip add with before_add association callback using "false"

As stated in the documentation: If a before_add callback throws an exception, the object does not get added to the collection

This way to prevent that save is very “ugly”.

It would be better to keep the standard of the other callback (like before_create): if it returns false, not saved.

Others users would also like it that way.

Thank you for the suggestion.

All callbacks now are only skipped if an exception is raised and we are removing the special meaning of false, so I think this behavior correct.