Add WorkAdventure to Custom communication systems (#2779)

README.md

@@ -344,6 +344,7 @@ _See also: [Comparison of CalDAV and CardDAV implementations - Wikipedia](https:
 - [Tox](https://tox.chat/) - Distributed, secure messenger with audio and video chat capabilities. ([Source Code](https://github.com/TokTok/c-toxcore)) `GPL-3.0` `C`
 - [Tuber](https://blog.trailofbits.com/2015/12/15/self-hosted-video-chat-with-tuber/) - Peer-to-peer video chat that works. ([Source Code](https://github.com/trailofbits/tubertc)) `MIT` `Javascript`
 - [WBO](https://github.com/lovasoa/whitebophir#wbo) -  A web Whiteboard to collaborate in real-time on schemas, drawings, and notes. ([Demo](https://wbo.ophir.dev/)) `AGPL-3.0` `Nodejs/Docker`
+- [WorkAdventure](https://workadventu.re) - A virtual office / virtual conference application presented as a 16-bit RPG video game. ([Demo](https://play.staging.workadventu.re/@/tcm/workadventure/wa-village), [Source Code](https://github.com/thecodingmachine/workadventure/)) `AGPL-3.0 + Commons Clause` `Docker`
 - [ZeroNet](https://zeronet.io/) `⚠` - Open, free, and uncensorable websites, using Bitcoin cryptography and BitTorrent network. ([Source Code](https://github.com/HelloZeroNet/ZeroNet)) `GPL-2.0` `Python`
 - [Zulip](https://zulip.org) - Zulip is a powerful, open source group chat application. ([Source Code](https://github.com/zulip/zulip)) `Apache-2.0/Other` `Python`