docs(readme): 增加文档地址

Author: feige996

README.md

@@ -29,9 +29,9 @@
 ![](https://raw.githubusercontent.com/andreasbm/readme/master/assets/lines/rainbow.png)
 
 <p align="center">
-  <a href="https://codercup.github.io/unibest/" target="_blank">📱 在线预览</a> 
-  <span style="margin:0 10px;">|</span> 
-  <a href="#" target="_blank">📖 阅读文档 (comming soon)</a>
+  <a href="https://codercup.github.io/unibest/" target="_blank">📱 在线预览</a>
+  <span style="margin:0 10px;">|</span>
+  <a href="https://codercup.github.io/unibest-docs/" target="_blank">📖 阅读文档</a>
 </p>
 
 ## ✨ 特性