Add README.md

Signed-off-by: Jelle van der Waa <jelle@vdwaa.nl>

README.md

+# conf.archlinux.org
+
+The source code for [conf.archlinux.org](https://conf.archlinux.org), uses hugo
+as static site generator.
+
+## Development
+
+The easiest is to start hugo in watch mode running a webserver.
+
+```
+hugo server -w --port=8080
+```