arch linux systemd how to set static ip on pi

view story

http://serverfault.com – I recently got my PI :) and decided to install arch linux and use it as a local webserver (command line only). However, I got stuck trying to set it to a static IP address, as systemd doesn't seem to recognise rc.conf. So my question is, how do I set the static IP address on arch linux on Raspberry Pi using systemd? Thanks (HowTos)