Enhance toc with some separation between links. Make contribution more obvvious. (docker#12)

Signed-off-by: Alex Ellis <alexellis2@gmail.com>

Author: alexellis

README.md

@@ -1,12 +1,21 @@
 # Docker Tutorials and Labs
 
-This repo contains [Docker](https://docker.com) tutorials authored both by Docker, and by members of the community. It's a growing repo which we intend to continue to grow, with help from the community.
+This repo contains [Docker](https://docker.com) labs and tutorials authored both by Docker, and by members of the community. We welcome contributions and want to grow the repo.
 
-Index:
+#### Docker tutorials:
 * [Docker for beginners] (beginner/readme.md)
 * [Docker for ASP.NET and Windows containers](windows/readme.md)
 * [Docker for Java Developers](java/readme.adoc)
+
+#### Community tutorials
 * [Docker Tutorials from the Community](https://github.com/docker/community/blob/master/tutorials/docker-tutorials.md) - links to a different repository
 * [Advanced Docker orchestration workshop] (https://github.com/docker/labs/tree/master/Docker-Orchestration) - links to a different repository
-* [Guide to submitting your own tutorial](contribute.md)
-* [Docker documentation](https://docs.docker.com)
+
+For more information on Docker, see the Official [Docker documentation](https://docs.docker.com).
+
+#### Contributing
+
+We want to see this repo grow, so if you have a tutorial to submit please see this guide:
+
+[Guide to submitting your own tutorial](contribute.md)
+