Update README.md

README.md

 * [Joomla](https://www.joomla.org/) - Another leading CMS.
 * [Magento](https://magento.com/) - The most popular ecommerce platform.
 * [WordPress](https://wordpress.org/) A blogging platform and CMS.
+* [Moodle](https://moodle.org/) Open-source learning platform.
 
 ### Components
 *Standalone components from web development frameworks and development groups.*