add wechat link (#349)

add joinus

README.md

@@ -33,6 +33,11 @@ PaddleClas is a toolset for image classification tasks prepared for the industry
 
 - Support Linux, Windows, macOS and other systems.
 
+## Community
+
+* Scan the QR code below with your Wechat, you can access to official technical exchange group. Look forward to your participation.
+
+![](docs/images/joinus.png)
 
 ## Tutorials
 

README_cn.md

@@ -37,6 +37,13 @@
 - 可运行于Linux、Windows、MacOS等多种系统。
 
 
+## 欢迎加入PaddleClas技术交流群
+
+* 微信扫描二维码加入官方交流群，获得更高效的问题答疑，与各行各业开发者充分交流，期待您的加入。
+
+![](docs/images/joinus.png)
+
+
 ## 文档教程
 
 - [快速安装](./docs/zh_CN/tutorials/install.md)