add Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International

License to README.md

Author: zkl94

README.md

@@ -2,6 +2,8 @@
 
 [![Join the chat at https://gitter.im/lao605/shadowsocks_analysis](https://badges.gitter.im/Join%20Chat.svg)](https://gitter.im/lao605/shadowsocks_analysis?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
 
+This work is licensed under a [Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License](http://creativecommons.org/licenses/by-nc-sa/4.0/").
+
 *此份代码仅用作学术交流用途，其他行为带来的后果本人概不负责*
 
 *This copy of code is for study of python only*