Update servers list

source/en/portal/servers/index.md

@@ -143,6 +143,7 @@ title: "Themed servers"
 
 ### 🐚 [Run by tech-savvy organizations](#run-by-tech-savvy-organizations)
 * [en.osm.town](https://en.osm.town) - for the OpenStreetMap Community *(Mastodon)*
+* [swiss-chaos.social](https://swiss-chaos.social) - Chaos Computer Club Switzerland *(Mastodon)*
 
 ### 🎉 [Notable mention](#notable-mention)
 // *are open to particular audience, i.e., to students of university*
@@ -171,6 +172,7 @@ title: "Themed servers"
 * [mastodon.uy](https://mastodon.uy) - Uruguay *(Mastodon)*
 * [chilemasto.casa](https://chilemasto.casa) - Chile *(Mastodon)*
 * [mastodon.ie](https://mastodon.ie) - Ireland *(Mastodon)*
+* [mastodon.org.uk](https://mastodon.org.uk) - UK *(Mastodon)*
 * [mastodon.me.uk](https://mastodon.me.uk) - UK tech community *(Mastodon)*
 * [rva.party](https://rva.party) - Richmond, USA *(Mastodon)*
 * [social.tulsa.ok.us](https://social.tulsa.ok.us) - Tulsa, Northeast Oklahoma, USA *(Mastodon)*
@@ -242,6 +244,7 @@ title: "Themed servers"
 * [dragonscave.space](https://dragonscave.space) - instance with a blind and visually impaired membership, welcome to everyone who is a nice person *(Mastodon)*
 * [mast.dragon-fly.club](https://mast.dragon-fly.club) - a Mastodon instance for internet users who want to find their own piece of peace *(Cloudflared)* *(Mastodon)*
 * [mastodon.gougere.fr](https://mastodon.gougere.fr) - Auxerre, France *(Mastodon)*
+* [stereodon.social](https://stereodon.social) - self-managed social network devoted to underground music (Italian, English languages) *(Mastodon)*
 
 ## Disclaimer
 `Following instances skipped`: number of users > 5.000, closed registration *at the moment of checking*, running old code, theme / description not understood due to language barrier or scarce description, long blocklists, experimental servers.