Update compose to use static ssh keys

This way rebuilding the docker container doesn't destroy its identity.
By copying the keys when the container starts, they won't be exposed through backing them into the image.

bin/update-compose

@@ -0,0 +1,4 @@
+#!/bin/bash
+
+docker pull debian:testing
+docker-compose up -d --force-recreate --build

cheesycompose/Dockerfile

@@ -38,4 +38,4 @@ VOLUME [ "/sys/fs/cgroup" ]
 
 STOPSIGNAL SIGRTMIN+3
 
-CMD ["/lib/systemd/systemd"]
+CMD ["sh", "-e", "-c", "cp -av /srv/cheesy.at/secrets/ssh/* /etc/ssh/; echo starting systemd; exec /lib/systemd/systemd"]