Update documentation link + readthedocs badge (#34)

README.md

@@ -1,6 +1,7 @@
 # fkit-learn: Functional Machine Learning
 
 ![PyPI](https://img.shields.io/pypi/v/fklearn.svg?style=flat-square)
+[![Documentation Status](https://readthedocs.org/projects/fklearn/badge/?version=latest)](https://fklearn.readthedocs.io/en/latest/?badge=latest)
 [![Gitter](https://badges.gitter.im/fklearn-python/community.svg)](https://gitter.im/fklearn-python/community?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge)
 [![CircleCI](https://circleci.com/gh/nubank/fklearn.svg?style=svg)](https://circleci.com/gh/nubank/fklearn)
 [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
@@ -19,7 +20,7 @@ The name is a tribute to the widely known [scikit-learn](https://scikit-learn.or
 
 
 [Getting Started]() |
-[Documentation]() |
+[Documentation](https://fklearn.readthedocs.io/en/latest/) |
 
 
 ## Installation