All the sources are on the repository dev.hubpress.io on the branch development.
Each commit build the minified version on the branch master and gh-pages.
If you want to see how work authentication, you can also have a look to the repository hubpress-plugin-github
Hi, I'm Anthonny, the creator of HubPress, give me the url of your github account to check if all is allright. You just have to go to this url: <url_of_your_github_pages_site>/hubpress, log in and then you can start to write