add quick example

README.md

@@ -33,6 +33,19 @@ Redistributable under a BSD-style open source license.
 See license.txt for more information.
 
 
+Quick Example
+-------------
+
+```  js
+var Showdown = require('showdown').Showdown
+var converter = new Showdown().converter()
+
+converter.makeHtml('#hello markdown!')
+
+// <h1 id='<h1 id="hellomarkdown">hello, markdown</h1>
+
+```
+
 What's it for?
 --------------