feat: initial docker installation support

Refs #1076

docker/etc/runit/runsvdir/default/dokku-init/finish

@@ -0,0 +1,15 @@
+#!/bin/bash
+
+exec >> /var/log/services/dokku-restore
+exec 2>&1
+
+if [[ "$1" -ne 0 ]]; then
+  echo "Error initializing dokku! Retrying in 30 seconds..."
+  exec sleep 30
+  exit 0
+fi
+
+echo "Done initializing dokku."
+exec sleep infinity
+
+exit 0

docker/etc/runit/runsvdir/default/dokku-init/run

@@ -0,0 +1,14 @@
+#!/bin/bash
+
+exec >> /var/log/services/dokku-init
+exec 2>&1
+
+echo "Running dokku-init"
+cd /tmp || exit 1
+
+if [[ -n "$DOKKU_HOSTNAME" ]]; then
+  echo "dokku dokku/vhost_enable boolean true" | debconf-set-selections
+  dokku --quiet domains:set-global "$DOKKU_HOSTNAME"
+fi
+
+exec dokku ps:restore

docker/etc/runit/runsvdir/default/nginx/run

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+exec >> /var/log/services/nginx
+exec 2>&1
+
+echo "Running nginx"
+exec /usr/sbin/nginx -c /etc/nginx/nginx.conf -g "daemon off;"

docker/etc/runit/runsvdir/default/rsyslog/run

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+exec >> /var/log/services/rsyslog
+exec 2>&1
+
+echo "Running rsyslog"
+exec /usr/sbin/rsyslogd -n