README: add Matrix channel
Change-Id: I3ff7e368b2bfe4b97fa8b048587af108dac73c4c
Reviewed-on: https://review.monogon.dev/c/monogon/+/2903
Reviewed-by: Serge Bazanski <serge@monogon.tech>
Tested-by: Jenkins CI
diff --git a/README.md b/README.md
index 57c2a4d..43122fc 100644
--- a/README.md
+++ b/README.md
@@ -2,7 +2,7 @@
This is the main repository containing the source code for the [Monogon Platform](https://monogon.tech).
-*This is pre-release software - take a look, and check back later!*
+*This is pre-release software - take a look, and check back later! In the meantime, join us on Matrix: [`#monogon-os-community:matrix.org`](https://app.element.io/#/room/#monogon-os-community:matrix.org)*.
## Environment