update readme.md

README.md

@@ -5,10 +5,19 @@ weed-fs
 [![GoDoc](https://godoc.org/github.com/chrislusf/weed-fs/go?status.svg)](https://godoc.org/github.com/chrislusf/weed-fs/go)
 [![RTD](https://readthedocs.org/projects/weed-fs/badge/?version=latest)](http://weed-fs.readthedocs.org/en/latest/)
 
+## Introduction
+
 An official mirror of code.google.com/p/weed-fs. 
 Moving to github.com to make cooperations easier. 
 This repo and the google code repo will be kept synchronized.
 
+## Usage
+
+```
+go get github.com/aszxqw/weed-fs/go/weed
+```
+
+## Reference
 
 For documents and bug reporting, Please visit
  http://weed-fs.googlecode.com