added link to source for dudle

README.md

@@ -1059,7 +1059,7 @@ See https://github.com/n1trux/awesome-sysadmin#metric--metric-collection
 
 - [Calagator](http://calagator.org/) - Event aggregator. ([Demo](http://calagator.org/), [Source code](https://github.com/calagator/calagator)) `MIT` `Ruby`
 - [Clerk](https://github.com/chr15m/Clerk) - Simple event logger to keep track of periodic events, habits, etc. as they occur. `GPL-3.0` `PHP`
-- [dudle](http://primelife.ercim.eu/results/opensource/63-dudle) - Online scheduling application. ([Demo](https://dudle.inf.tu-dresden.de/)) `AGPL-3.0` `Ruby`
+- [dudle](http://primelife.ercim.eu/results/opensource/63-dudle) - Online scheduling application. ([Demo](https://dudle.inf.tu-dresden.de/), [Source code](https://github.com/kellerben/dudle)) `AGPL-3.0` `Ruby`
 - [Fider](http://getfider.com) - Open source alternative to UserVoice for customer feedback. ([Demo](https://demo.fider.io), [Source Code](https://github.com/getfider/fider)) `MIT` `Go`
 - [Framadate](https://framadate.org/) - Online service for planning an appointment or make a decision quickly and easily: Make a poll, Define dates or subjects to choose, Send the poll link to your friends or colleagues, Discuss and make a decision. ([Demo](https://framadate.org/aqg259dth55iuhwm), [Source Code](https://git.framasoft.org/framasoft/framadate)) `CECILL-B` `PHP`
 - [Kyélà](http://kyela.net/) - Participation polls for group events. ([Demo](http://kyela.net/55232734237c8/), [Source Code](https://github.com/abienvenu/Kyela)) `AGPL-3.0` `PHP`