Parent and child category creation


I am currently creating an online store in RoR. For the administration
screens, I want to be able to allow new Parent categories and Child
categories to be created or deleted but I am a little unsure of how to
do this.

What I would also like to happen is for the menu of the online store to
update - based on the parent and child categories created in the admin
system, and then obviously to add products into these categories.

I wondered if anyone has produced a similar solution and mgiht be able
to share or advise of how I can proceed?

Thank you.