Initial Docker deployment setup

docker/mariadb-entrypoint.sh

@@ -0,0 +1,8 @@
+#!/bin/sh
+# Prepare the external table directory. Then, start MariaDB.
+set -eu
+
+mkdir -p /var/lib/mysqlext
+chown mysql:mysql /var/lib/mysqlext
+
+exec /usr/local/bin/docker-entrypoint.sh "$@"