update readme

Author: fengjian

README.md

@@ -65,8 +65,18 @@ ActivityLess.$noTitle(this);
 ActivityLess.$fullScreen(this);
 ```
 
+## Proguard
+```
+-dontwarn com.jayfeng.lesscode.**
+```
+
 See more details on the [Wiki](https://github.com/openproject/LessCode/wiki)
 
+## Alternative libraries
+* [xUtils3](https://github.com/wyouflf/xUtils3)
+* [LiteCommon](https://github.com/litesuits/android-common)
+* [TrineaAndroidCommon](https://github.com/Trinea/android-common)
+
 ## Author
 
 > Author weibo：<a href="http://weibo.com/xiaofengjian" target="_blank">冯建V</a>&nbsp;&nbsp;&nbsp;&nbsp;mail：673592063@qq.com&nbsp;&nbsp;&nbsp;&nbsp;QQ：673592063