Update docs host from `readthedocs.org` to `readthedocs.io`

README.md

@@ -2,7 +2,7 @@
 
 [![Google Group](https://img.shields.io/badge/-Google%20Group-lightgrey.svg)](https://groups.google.com/forum/#!forum/jupyter)
 [![Build Status](https://travis-ci.org/jupyter/notebook.svg?branch=master)](https://travis-ci.org/jupyter/notebook)
-[![Documentation Status](https://readthedocs.org/projects/jupyter-notebook/badge/?version=latest)](http://jupyter-notebook.readthedocs.org/en/latest/?badge=latest)
+[![Documentation Status](https://readthedocs.io/projects/jupyter-notebook/badge/?version=latest)](http://jupyter-notebook.readthedocs.org/en/latest/?badge=latest)
 
 The Jupyter notebook is a web-based notebook environment for interactive
 computing.
@@ -24,12 +24,12 @@ discrete repos.
 
 ## Installation
 You can find the installation documentation for the
-[Jupyter platform, on ReadTheDocs](http://jupyter.readthedocs.org/en/latest/install.html).
+[Jupyter platform, on ReadTheDocs](http://jupyter.readthedocs.io/en/latest/install.html).
 The documentation for advanced usage of Jupyter notebook can be found
-[here](http://jupyter-notebook.readthedocs.org/en/latest).
+[here](http://jupyter-notebook.readthedocs.io/en/latest).
 
 For a local installation, make sure you have
-[pip installed](https://pip.readthedocs.org/en/stable/installing/) and run:
+[pip installed](https://pip.readthedocs.io/en/stable/installing/) and run:
 
     $ pip install notebook
 
@@ -52,7 +52,7 @@ If you are interested in contributing to the project, see [`CONTRIBUTING.rst`](C
 ## Resources
 - [Project Jupyter website](https://jupyter.org)
 - [Online Demo at try.jupyter.org](https://try.jupyter.org)
-- [Documentation for Jupyter notebook](http://jupyter-notebook.readthedocs.org/en/latest/) [[PDF](https://media.readthedocs.org/pdf/jupyter-notebook/latest/jupyter-notebook.pdf)]
-- [Documentation for Project Jupyter](http://jupyter.readthedocs.org/en/latest/index.html) [[PDF](https://media.readthedocs.org/pdf/jupyter/latest/jupyter.pdf)]
+- [Documentation for Jupyter notebook](http://jupyter-notebook.readthedocs.io/en/latest/) [[PDF](https://media.readthedocs.io/pdf/jupyter-notebook/latest/jupyter-notebook.pdf)]
+- [Documentation for Project Jupyter](http://jupyter.readthedocs.io/en/latest/index.html) [[PDF](https://media.readthedocs.io/pdf/jupyter/latest/jupyter.pdf)]
 - [Issues](https://github.com/jupyter/notebook/issues)
 - [Technical support - Jupyter Google Group](https://groups.google.com/forum/#!forum/jupyter)