Good practice, license in readme file

It's very interesting for forks too.

Author: rafaelstz

README.md

@@ -79,3 +79,7 @@ To report security vulnerabilities in Magento software or web sites, please e-ma
 
 Stay up-to-date on the latest vulnerabilities and patches for Magento by signing up for <a href="https://magento.com/security/sign-up">Security Alert Notifications</a>.
 
+<h2>License</h2>
+
+OSL 3.0 (c) [Magento Inc.](https://github.com/magento/)
+