I just created this repository:
I then setup A records for it via my domain provider. After that I pushed test page to gh-pages. When I go to settings > gh-pages it just says:
Your GitHub Pages site is currently being built from the gh-pages branch.
And there is no custom domain option. I wish to serve the url `test-deploy.fireflysemantics.com` and on the other repositories that I'm serving from a sub domain this is all possible. Thoughts?
Helps arrived! The gh-pages that GitHub is refering to is the branch of the repository that is deployed, not the URL that it's deployed to. Under that section, there should be a section that is titled Custom domain. Here, you can enter the custom domain that you wish for the site to be deployed to. As long as you've configured the DNS correctly (which it looks like you have), then it should push to that domain.
There's some more info about this over here.
I know that you have to create a file named CNAME with the custom domain, and in the DNS you have to redirect the domain to GitHub :)