rConfig: add source code link, license, language

- ref. #416

README.md

@@ -578,7 +578,7 @@ _See also: [IT Asset Management]([Ralph](#it-asset-management))_
 - [Oxidized](https://github.com/ytti/oxidized) - A modern take on network device configuration monitoring with web interface and GIT storage. `Apache-2.0` `Ruby`
 - [phpIPAM](http://phpipam.net/) - Open source IP address management with PowerDNS integration. ([Source Code](https://github.com/phpipam/phpipam)) `GPL-3.0` `PHP`
 - [RANCID](http://www.shrubbery.net/rancid/) - Monitors network device's configuration and maintain history of changes. ([Source Code](https://github.com/haussli/rancid)) `BSD-3-Clause` `Perl/Shell`
-- [rConfig](http://www.rconfig.com/) - Another network device configuration management tool.
+- [rConfig](http://www.rconfig.com/) - Another network device configuration management tool. ([Source Code](https://github.com/rconfig/rconfig)) `GPL-3.0` `PHP`
 - [trigger](https://github.com/trigger/trigger) - Robust network automation toolkit written in Python.