Setting up another blog

I have a site: https://www.barryjogorman.com – built on wordpress 3.0.4. basically I use this as my blog. Site has some pages describing services I offer.

I am currently learning Ruby on Rails. I want to maintain a blog detailing my learning experiences. I would like to have this on a blog: https://www.barryjogorman.com/learningrubyonrails. How do I set this up? Do I require another installation of wordpress? Is it better to go with https://learningrubyonrails.barryjogorman.com?

All help/ guidance greatly appreciated.