Update README.md

Author: Milan Aryal

README.md

@@ -396,6 +396,7 @@
 | Name | Description |
 |---|---|
 | [Can I Use](http://caniuse.com/) | Check the browser compatibility of CSS3 and HTML5 properties. |
+| [Should I Prefix](http://shouldiprefix.com/) | Simply show what prefixes are needed for a newer CSS property. |
 
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