Added documentation to README file

docs/prerequisites.md

@@ -1,6 +1,6 @@
 # Prerequisites
 
-- An x86 server running **CentOS** (7 only for now; [8 is not yet supported](https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/300)), **Debian** (9/Stretch+) or **Ubuntu** (16.04+). This playbook doesn't support running on ARM ([see](https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/299)), however a minimal subset of the tools can be built on the host, which may result in a working configuration, even on a Raspberry pi (see [Self-Building](self-building.md)). We only strive to support released stable versions of distributions, not betas or pre-releases. This playbook can take over your whole server or co-exist with other services that you have there.
+- An x86 server running **CentOS** (7 only for now; [8 is not yet supported](https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/300)), **Debian** (9/Stretch+), **Ubuntu** (16.04+), or **Archlinux**. This playbook doesn't support running on ARM ([see](https://github.com/spantaleev/matrix-docker-ansible-deploy/issues/299)), however a minimal subset of the tools can be built on the host, which may result in a working configuration, even on a Raspberry pi (see [Self-Building](self-building.md)). We only strive to support released stable versions of distributions, not betas or pre-releases. This playbook can take over your whole server or co-exist with other services that you have there.
 
 - `root` access to your server (or a user capable of elevating to `root` via `sudo`).