Add FChannel, which implemented ActivityPub.

Add FChannel, which implemented ActivityPub. FChannel is a libre, self-hostable, federated, imageboard platform that utilizes ActivityPub:

https://activitypub.rocks/
https://en.wikipedia.org/wiki/ActivityPub
https://www.w3.org/TR/activitypub/

There are currently several instances federated with each other. For a complete list, see:

https://fchannel.org/instance-index.html
https://fchan.xyz/

Get the server code here:

https://github.com/FChannel0/FChannel-Server
https://git.fchannel.org/

README.md

@@ -16,6 +16,7 @@ name | language/stack | comments | notable deployments
 [Kareha](http://wakaba.c3.cx/s/web/wakaba_kareha) | Perl + RDBMS | textboard-only version of Wakaba |
 [TinyIB](https://code.rocketnine.space/tslocum/TinyIB) | PHP + MySQL | Inspired by Futaba and Futallaby | 
 [Lainchan](https://github.com/lainchan/lainchan/) | PHP + MySQL | Fork of vichan | [Lainchan](https://lainchan.org/)
+[FChannel](https://github.com/FChannel0/FChannel-Server) | Go + PostgreSQL | a libre, self-hostable, federated, imageboard platform that utilizes [ActivityPub](https://www.w3.org/TR/activitypub/) | [fchannel.org](https://fchannel.org/), [fchan.xyz](https://fchan.xyz/), [usagi.reisen](https://usagi.reisen/), [penchan.xyz](https://penchan.xyz/), [poopchan.org](https://poopchan.org/), [chan.cum.salon](https://chan.cum.salon/), [chan.getgle.org](https://chan.getgle.org/)
 
 
 ## Various other