Add Calagator (#746)

* Add Calagator

* Add link

README.md

@@ -766,6 +766,7 @@ See https://github.com/n1trux/awesome-sysadmin#monitoring and https://github.com
 
 ## Polls and Events
 
+  * [Calagator](http://calagator.org/) - An event aggregator. ([Demo](http://calagator.org/), [Source code](https://github.com/calagator/calagator)) `MIT` `Ruby`
   * [dudle](http://primelife.ercim.eu/results/opensource/63-dudle) - An online scheduling application. ([Demo](https://dudle.inf.tu-dresden.de/)) `AGPLv3` `Ruby`
   * [Framadate](https://framadate.org/) - An 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))