ReadtheDoc doens't automatically generate py-modindex.html

I am using sphinx to document my project. The build-in index.rst file has:

Indices and tables
------------------

* :ref:`genindex`
* :ref:`modindex`
* :ref:`search`

which automatically generate a py-modindex.html page. This functions very good on my local machine.

So I am trying to host the doc on readthedoc.org. But, what readthedoc do is go to my github, locate the conf.py, generate all html. But since

* :ref:`modindex` 

requires all module importable from local, they may not did that. Hence I cannot see the py-modindex.html page. Any idea how to bring it back?

This is my readthedoc page: http://ift.tt/1IP7Osn

This the page I want (but it's not on): http://ift.tt/1J7eHsu

This is github project page: http://ift.tt/1IP7M3F

via Chebli Mohamed