update doc add release link

README.md

-![SOAR](http://github.com/XiaoMi/soar/raw/master/doc/images/logo.png)
+![SOAR](https://raw.githubusercontent.com/XiaoMi/soar/master/doc/images/logo.png)
 
 [![Gitter](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/xiaomi-dba/soar) [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](http://github.com/XiaoMi/soar/blob/master/LICENSE)
 

doc/install.md

 ## 下载二进制安装包
 
 ```bash
-TODO: 开源后补充下载release版本链接
-wget https://github.com/XiaoMi/soar/archive/v0.7.0.zip
+wget https://github.com/XiaoMi/soar/releases/download/${tag}/soar.linux-amd64 -O soar
+
+如：
+wget https://github.com/XiaoMi/soar/releases/download/v0.8.0/soar.linux-amd64 -O soar
 ```
 
 ## 源码安装