To build RapidSMS documentation, you need the sphinx python documentation
engine. On Debian-based systems, it should be available in the python-sphinx package.
See also http://sphinx.pocoo.org/

The docs directory is a partial copy of the Django documentation structure to be
used as a model to construct RapidSMS Documentation.
You can build it with the following command:
sphinx-build docs $DOCSPUBLIC

The source directory contains the real RapidSMS documentation.
You can build it with the following command:
sphinx-build source $DOCSPUBLIC

$DOCSPUBLIC should be an existing directory where the built HTML files will be stored.