Add Takahē to Social Networking and Forum software (#3471)

Co-authored-by: nodiscc <nodiscc@gmail.com>

README.md

@@ -556,6 +556,7 @@ Simple deployment of [E-mail](https://en.wikipedia.org/wiki/Email) servers, e.g.
 - [Scoold](https://scoold.com) - Stack Overflow in a JAR. An enterprise-ready Q&A platform with full-text search, SAML, LDAP integration and social login support. ([Demo](https://live.scoold.com), [Source Code](https://github.com/Erudika/scoold)) `Apache-2.0` `Java`
 - [Simple Machines Forum](https://www.simplemachines.org/) - Free, professional grade software package that allows you to set up your own online community within minutes. ([Source Code](https://github.com/SimpleMachines/SMF2.1)) `BSD-3-Clause` `PHP`
 - [Socialhome](https://socialhome.network) - Federated and decentralized profile builder and social network engine. ([Demo](https://socialhome.network/), [Source Code](https://github.com/jaywink/socialhome)) `AGPL-3.0` `Python`
+- [Takahē](https://jointakahe.org/) - Federated microblogging server. Mastodon, & ActivityPub compatible. ([Source Code](https://github.com/jointakahe/takahe)) `BSD-3-Clause` `Docker`
 - [Talkyard](https://www.talkyard.io/) - Create a community, where your users can suggest ideas and get questions answered. And have friendly open-ended discussions and chat (Slack/StackOverflow/Discourse/Reddit/Disqus hybrid). ([Demo](https://www.talkyard.io/forum/latest), [Source Code](https://github.com/debiki/talkyard)) `AGPL-3.0` `Scala`
 - [Teddit](https://teddit.net) `⚠` - Alternative Reddit front-end focused on privacy. ([Source Code](https://codeberg.org/teddit/teddit)) `AGPL-3.0` `Nodejs`
 - [Thredded](https://github.com/thredded/thredded) - Forums, feature-rich and simple. `MIT` `Ruby`