Lock version of docker-osx on home page

docs/index.md

@@ -49,7 +49,7 @@ Let's get a basic Python web app running on Fig. It assumes a little knowledge o
 
 First, install Docker. If you're on OS X, you can use [docker-osx](https://github.com/noplay/docker-osx):
 
-    $ curl https://raw.github.com/noplay/docker-osx/master/docker-osx > /usr/local/bin/docker-osx
+    $ curl https://raw.github.com/noplay/docker-osx/0.7.6/docker-osx > /usr/local/bin/docker-osx
     $ chmod +x /usr/local/bin/docker-osx
     $ docker-osx shell