Inheritance design question

inheritance is overused… it should be used when the subclass is a more specific instance of the base class in a natural way.

Ferrari < Car
Dog < Animal
Tennis < Sport

A [Project] is not naturally related to a [Page], it’s only displayed on it but there is no logical relationship of any kind.

In your case I would use a ruby module

module PageItem
attr_accessor :title, :description
def to_rss