Adding doc status

README.md

@@ -1,6 +1,6 @@
 ## netboot.xyz
 
-[![Build Status](https://travis-ci.org/antonym/netboot.xyz.svg?branch=master)](https://travis-ci.org/antonym/netboot.xyz)
+[![Build Status](https://travis-ci.org/antonym/netboot.xyz.svg?branch=master)](https://travis-ci.org/antonym/netboot.xyz) [![Doc Status](https://readthedocs.org/projects/netbootxyz/badge/?version=latest)](https://readthedocs.org/projects/netbootxyz)
 
 ### What is netboot.xyz?