update readme file

Signed-off-by: Peng Xiao <xiaoquwl@gmail.com>

README.rst

@@ -6,11 +6,15 @@ Docker Kubernetes Lab Handbook
 This handbook contains some docker and kubernetes lab tutorials. It will be useful if you are learning docker or kubernetes now.
 Please go to http://docker-k8s-lab.readthedocs.io/en/latest/ for details
 
-And, I created a course on Udemy, it includes more information about docker, https://www.udemy.com/learning-docker-and-k8s-by-practice/?couponCode=DOCKER-10-ONLY
+And, I created some Chinese courses on Udemy, include docker/k8s courses, https://github.com/udemy-course/Promotion
 
 Any issues or suggestions, welcome to create issue or PR on GitHub.
 
+中国的朋友也欢迎关注我的个人微信公众号 |wechat|
+
 .. |License| image:: https://img.shields.io/hexpm/l/plug.svg
    :target: https://github.com/xiaopeng163/docker-k8s-lab/blob/master/LICENSE
 .. |Documentation Status| image:: https://readthedocs.org/projects/docker-k8s-lab/badge/?version=latest
    :target: http://docker-k8s-lab.readthedocs.io/en/latest/?badge=latest
+
+.. |wechat| image:: https://github.com/xiaopeng163/static/blob/master/QR/MY_WeChat_official_account.jpg