Update docs

Related to #425 (Github Pull Request).

CHANGELOG.md

@@ -1,3 +1,10 @@
+# 2020-03-29
+
+## Archlinux support
+
+Thanks to [Christian](https://github.com/christianlupus)'s efforts, the playbook now supports installing to an [Archlinux](https://www.archlinux.org/) server.
+
+
 # 2020-03-24
 
 ## Jitsi support

README.md

@@ -75,7 +75,7 @@ This is similar to the [EMnify/matrix-synapse-auto-deploy](https://github.com/EM
 
 - this one **can be re-ran many times** without causing trouble
 
-- works on both **CentOS** (7.0+) and Debian-based distributions (**Debian** 9/Stretch+, **Ubuntu** 16.04+)
+- works on various distros: **CentOS** (7.0+), Debian-based distributions (**Debian** 9/Stretch+, **Ubuntu** 16.04+), **Archlinux**
 
 - this one installs everything in a single directory (`/matrix` by default) and **doesn't "contaminate" your server** with files all over the place