Keep track of which projects are using which theme.
Keep track of which projects are using which theme.

This is primarily used so we can send email to folks using alabaster,
and other themes we might want to display ads on.
This will allow us to give people fair warning before we put ads on their docs.

safwanrahman/readthedocs.org,pombredanne/readthedocs.org,safwanrahman/readthedocs.org,pombredanne/readthedocs.org,safwanrahman/readthedocs.org,rtfd/readthedocs.org,davidfischer/readthedocs.org,rtfd/readthedocs.org,rtfd/readthedocs.org,pombredanne/readthedocs.org,davidfischer/readthedocs.org,davidfischer/readthedocs.org,safwanrahman/readthedocs.org,davidfischer/readthedocs.org,rtfd/readthedocs.org