Fix queue show error & Add demo

Signed-off-by: Monokaix <[email protected]>

Author: Monokaix

README.md

@@ -1,9 +1,11 @@
 # Volcano dashboard
 
-## Introduction
+## Overview
 
 The volcano dashboard provides a basic dashboard that can be easily deployed in your kubernetes cluster to show the status of resources including volcano jobs, queues, pods, etc.
 
+<img src="docs/images/demo.gif" alt="volcano dashboard" style="zoom:50%;" />
+
 ## Design
 
 You can follow the [design doc](docs/design.md) to learn more about the design details.