GitHub Project Page on Subdomain of GitHub User Page

I have  been wondering on how to put GitHub Project Page into subdomain of my GitHub User Page as no detailed instructions can be found around. In case you don't understand what I want to achieve, say I already have my GitHub User Page (hansnewbie.github.io) to use custom domain to hansadrian.com (you should follow the guide at http://davidensinger.com/2013/03/setting-the-dns-for-github-pages-on-namecheap/ - I am using Namecheap since it is cheap, as the name suggests). Now, I would like my GitHub Blog Project Page (hansnewbie.github.io/blog) - which is automatically redirected to hansadrian.com/blog - to use custom subdomain of blog.hansadrian.com.

The way to do this is apparently very easy. Again, I am using Namecheap so the steps might be different for different host. Go to your All Host Record. Under custom subdomain, add a new entry with the following inputs:

Host Name - subdomain name that you want : blog
IP Address/URL - username.github.io. : hansnewbie.github.io. (don't forget the trailing dot)
Record Type - CNAME
TTL - 1800

That's all for the DNS configuration. Don't forget in your GitHub Project Page repo, add a CNAME file that contains subdomain.domain.com (in my case, I will have CNAME file with the content blog.hansadrian.com).