update readme

Author: litefeel

README.md

@@ -81,13 +81,15 @@ You can also activate the Markdown module from [Jetpack](https://wordpress.org/p
 
 ### GitHub directory structure ###
 
+~~~
 .
 ├── _pages
 |   └── 2007-10-29-some-pages.md
 ├── _posts
 |   └── 2009-04-26-some-posts.md
 └── images
     └── some-images # copy all files (include subdirectory) to wordpress
+~~~
 
 ### Importing from GitHub ###