doc: readme修改

README.md

@@ -17,9 +17,11 @@ npm i docsify-cli -g
 Preview your local site
 
 ```bash
-docsify serve docs
+docsify serve
 ```
 
+Then, open Brower  http://localhost:3000
+
 ## Writing article
 If you create a file named new-article.md, then it is accessible via /#/new-article, in order to have sidebar, then you can write your new routes in _sidebar.md.