added link to source for OpenProject

README.md

@@ -1129,7 +1129,7 @@ _See also [Ticketing](#ticketing), [Task management/To-do lists](#task-managemen
 - [Klaus](https://github.com/jonashaag/klaus/) - Simple, easy-to-set-up Git web viewer that Just Works. `ISC` `Python`
 - [Lavagna](http://lavagna.io) - Lavagna is an open-source issue/project management tool designed for small teams. Lightweight, pure Java, easy to install, easy to use. ([Source Code](https://github.com/digitalfondue/lavagna)) `GPL-3.0` `Java`
 - [Octobox](https://octobox.io/) `⚠` - Take back control of your GitHub Notifications. ([Source Code](https://github.com/octobox/octobox)) `AGPL-3.0` `Ruby`
-- [OpenProject](https://www.openproject.org) - OpenProject is a web-based project management system. `GPL-3.0` `Ruby`
+- [OpenProject](https://www.openproject.org) - OpenProject is a web-based project management system. ([Source Code](https://github.com/opf/openproject)) `GPL-3.0` `Ruby`
 - [Phabricator](http://phabricator.org/) - Collection of web applications that help build better software. ([Demo](https://secure.phabricator.com/), [Source Code](https://github.com/phacility/phabricator)) `Apache-2.0` `PHP`
 - [Phproject](http://www.phproject.org/) - High performance full-featured project management system. ([Demo](http://demo.phproject.org/), [Source Code](https://github.com/Alanaktion/phproject)) `GPL-3.0` `PHP`
 - [Redmine](http://www.redmine.org/) - Redmine is a flexible project management web application. ([Demo](http://demo.redmine.org/), [Source Code](https://svn.redmine.org/redmine/)) `GPL-2.0` `Ruby`