amerine/acts_as_tree — pull request #8 by scootklein (2012-11-16 15:31:47+00:00)
Title: allow callbacks for after add and remove from parent

I wasn't too sure if we wanted to add additional callbacks for before_add and before_remove as well, in which case we may just want a top level `:callbacks` configuration option that takes a hash of the callbacks that are desired (deep hash merge here). I guess this will do for now and we can refactor later if necessary.