Update README.md

Author: lingcoder

README.md

@@ -65,7 +65,7 @@
 
 ## 一起交流
 
-交流群：721698221 <a target="_blank" href="//shang.qq.com/wpa/qunwpa?idkey=4cb8bdc26879e544a0e1c2027305afef699029d5c0f314099a239b7c4f309c5f"><img border="0" src="https://raw.githubusercontent.com/LingCoder/OnJava8/master/docs/images/qqgroup.png" alt="OnJava8翻译交流" title="OnJava8翻译交流"></a>( 点击图标即可加入 )<br>
+交流群：721698221 <a target="_blank" href="//shang.qq.com/wpa/qunwpa?idkey=4cb8bdc26879e544a0e1c2027305afef699029d5c0f314099a239b7c4f309c5f"><img border="0" src="https://raw.githubusercontent.com/LingCoder/OnJava8/master/docs/images/qqgroup.png" alt="OnJava8翻译交流" title="OnJava8翻译交流"></a>( 点击图标即可加入 )<br> 加群时请简单备注下来源或说明
 
 <div align="left">
 <img src="https://raw.githubusercontent.com/LingCoder/OnJava8/master/assets/QQGroupQRCode.png"  alt="QQGroupQRCode"/>