remove thredded homepage and demo links (website down - no such app.)

README.md

@@ -480,7 +480,7 @@ _[SIP](https://en.wikipedia.org/wiki/Session_Initiation_Protocol)/[IPBX](https:/
 - [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`
 - [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`
 - [Tokumei](https://tokumei.co/) - Anonymous microblogging platform. ([Source Code](https://gitlab.com/tokumei/tokumei)) `ISC` `rc`
-- [Thredded](https://thredded.org) - Forums, feature-rich and simple. ([Demo](https://thredded.org/thredded), [Source Code](https://github.com/thredded/thredded)) `MIT` `Ruby`
+- [Thredded](https://github.com/thredded/thredded) - Forums, feature-rich and simple. `MIT` `Ruby`
 - [twister](http://twister.net.co/) - Fully decentralized P2P microblogging platform leveraging the free software implementations of Bitcoin and BitTorrent protocols. ([Source Code](https://github.com/miguelfreitas/twister-core)) `MIT` `C++`
 - [twtxt.net](https://twtxt.net) - a Self-Hosted, Twitter™-like Decentralised micro-logging platform. No ads, no tracking, your content, your data. ([Source Code](https://github.com/prologic/twtxt)) `MIT` `Go`
    - [rss2twtxt](https://github.com/prologic/rss2twtxt) - An RSS/Atom feed aggregator command-line tool and web service that consume RSS/Atom and produces twtxt.net feeds for consumption by twtxt clients. ([Demo](https://feeds.twtxt.net)) `MIT` `Go`