Link to docs in README.rst

Resolves googleapis#5

Author: Jon Wayne Parrott

README.rst

@@ -5,6 +5,10 @@ oauthlib integration for Google Auth
 
 This library provides `oauthlib`_ integration with `google-auth`_.
 
+.. |build| image:: https://travis-ci.org/GoogleCloudPlatform/google-auth-library-python-oauthlib.svg?branch=master
+   :target: https://travis-ci.org/GoogleCloudPlatform/google-auth-library-python-oauthlib
+.. |docs| image:: https://readthedocs.org/projects/google-auth-oauthlib/badge/?version=latest
+   :target: https://google-auth-oauthlib.readthedocs.io/en/latest/
 .. |pypi| image:: https://img.shields.io/pypi/v/google-auth-oauthlib.svg
    :target: https://pypi.python.org/pypi/google-auth-oauthlib
 
@@ -20,6 +24,13 @@ You can install using `pip`_::
 
 .. _pip: https://pip.pypa.io/en/stable/
 
+Documentation
+-------------
+
+The latest documentation is available at `google-auth-oauthlib.readthedocs.io`_.
+
+.. _google-auth-oauthlib.readthedocs.io: http://google-auth-oauthlib.readthedocs.io/
+
 License
 -------