Updated README.

README.md

@@ -2,4 +2,19 @@
 
 ![travis](https://travis-ci.com/k82cn/volcano.svg?token=Qogbzw9M3Q6qBwA56otg&branch=master)
 
-A Kubernetes-based system for high performance workload.
+Volcano is a Kubernetes-based system for high performance workload, providing mechanisms for applications
+which would like to run high performance workload leveraging Kubernetes, e.g. Tensorflow, Spark, MPI.
+
+Volcano builds upon a decade and a half of experience on running high performance workload workloads at scale
+using several systems, combined with best-of-breed ideas and practices from the open source community.
+
+## Overall Architecture
+
+![volcano](docs/images/volcano-intro.png)
+
+## Community, discussion, contribution, and support
+
+You can reach the maintainers of this project at:
+
+Slack: #volcano-sh
+Mailing List: https://groups.google.com/forum/#!forum/volcano-sh