Update README.markdown

Author: daninus14

README.markdown

@@ -649,8 +649,9 @@ If you build a binary, reference a DB driver in your dependencies:
 
 ## Mito Extensions and Plugins
 
-* [mito-attachment](https://github.com/fukamachi/mito-attachment)
-* [mito-auth](https://github.com/fukamachi/mito-auth)
+* [mito-attachment](https://github.com/fukamachi/mito-attachment) To ease storing files in the filesystem with a DB representation
+* [mito-auth](https://github.com/fukamachi/mito-auth) To ease handling DB storage of authentication details
+* [mito-validate](https://github.com/daninus14/mito-validate) To ease validating mito class slots and objects
 
 ## See Also