guides / routing: should mention shallow option for nested resources

I'm not (yet) confident enough to clone and edit the documents. But I do suggest that:

   Rails Routing from the Outside In — Ruby on Rails Guides

needs make mention of :shallow => true (even if in passing) -- it's too important not to be documented there, and the only other descriptions appear to be Rails vintage 2.2.

Two questions: where would you put it and how would you describe it? It sounds like you know more than you think :slight_smile: