First initialize and pull the submodule containing the Sphinx theme. Do this from the top directory of rootpy (not here in docs):

git submodule init
git submodule update

To build the docs as html (you need Sphinx installed):

make html

or simply (html is the default):

make

The built html is then found in _build/html. To preview the docs locally before uploading:

make show

If you have not done so already, add a reference to the main rootpy repository from your fork:

git remote add upstream git@github.com:rootpy/rootpy

Create a local branch that tracks the main gh-pages branch:

git fetch upstream
git branch gh-pages upstream/gh-pages

To upload the docs to http://rootpy.github.com/rootpy/ install ghp-import:

pip install ghp-import

and from the top directory of rootpy (not here in docs):

ghp-import -r upstream -p docs/_build/html/