add link to pypa-dev list

Author: qwcode

docs/index.rst

@@ -3,7 +3,8 @@ pip
 
 A tool for installing and managing Python packages.
 
-`Mailing list <http://groups.google.com/group/python-virtualenv>`_ ``|``
+`User list <http://groups.google.com/group/python-virtualenv>`_ ``|``
+`Dev list <http://groups.google.com/group/pypa-dev>`_ ``|``
 `Issues <https://github.com/pypa/pip/issues>`_ ``|``
 `Github <https://github.com/pypa/pip>`_ ``|``
 `PyPI <https://pypi.python.org/pypi/pip/>`_ ``|``