Add docker image entrypoint and quickstart sample

Dockerfile

@@ -38,3 +38,5 @@ RUN apt -q update && \
     apt -qq -y --purge autoremove && \
     apt -qq -y clean && \
     rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/* /var/cache/* /var/log/*
+
+CMD [ "/usr/local/sbin/haproxy", "-W", "-db", "-f", "/etc/haproxy/haproxy.cfg" ]

README.md

@@ -2,7 +2,13 @@
 
 Build scripts for HAProxy with QUIC
 
-## Get started
+**PROJECT STATUS**: Alpha, untested, probably unstable
+
+## Quickstart
+
+    docker run -it -v /path/to/haproxy.cfg:/etc/haproxy/haproxy.cfg:ro registry.gitlab.com/mangadex-pub/haproxy:2.6-bullseye
+
+## Build it
 
 You will need the following dependencies (Debian/Ubuntu packages given as example):