Fix missing space in header

README.md

@@ -11,10 +11,10 @@
 
 
 [![PyPI](https://img.shields.io/pypi/v/jupyterhub.svg)](https://pypi.python.org/pypi/jupyterhub)
-[![Documentation Status](https://readthedocs.org/projects/jupyterhub/badge/?version=latest)](http://jupyterhub.readthedocs.org/en/latest/?badge=latest) 
+[![Documentation Status](https://readthedocs.org/projects/jupyterhub/badge/?version=latest)](http://jupyterhub.readthedocs.org/en/latest/?badge=latest)
 [![Build Status](https://travis-ci.org/jupyterhub/jupyterhub.svg?branch=master)](https://travis-ci.org/jupyterhub/jupyterhub)
 [![Circle CI](https://circleci.com/gh/jupyterhub/jupyterhub.svg?style=shield&circle-token=b5b65862eb2617b9a8d39e79340b0a6b816da8cc)](https://circleci.com/gh/jupyterhub/jupyterhub)
-[![codecov.io](https://codecov.io/github/jupyterhub/jupyterhub/coverage.svg?branch=master)](https://codecov.io/github/jupyterhub/jupyterhub?branch=master) 
+[![codecov.io](https://codecov.io/github/jupyterhub/jupyterhub/coverage.svg?branch=master)](https://codecov.io/github/jupyterhub/jupyterhub?branch=master)
 [![Google Group](https://img.shields.io/badge/google-group-blue.svg)](https://groups.google.com/forum/#!forum/jupyter)
 
 With [JupyterHub](https://jupyterhub.readthedocs.io) you can create a
@@ -49,7 +49,7 @@ for administration of the Hub and its users.
 
 ## Installation
 
-###Check prerequisites
+### Check prerequisites
 
 - [Python](https://www.python.org/downloads/) 3.3 or greater
 - [nodejs/npm](https://www.npmjs.com/) Install a recent version of
@@ -232,4 +232,4 @@ our JupyterHub [Gitter](https://gitter.im/jupyterhub/jupyterhub) channel.
 **[Docker](#docker)** |
 **[Contributing](#contributing)** |
 **[License](#license)** |
-**[Help and Resources](#help-and-resources)**
+**[Help and Resources](#help-and-resources)**