Add initial "redis"

redis/Dockerfile

@@ -0,0 +1,5 @@
+FROM redis
+
+COPY docker-healthcheck /usr/local/bin/
+
+HEALTHCHECK CMD ["docker-healthcheck"]

redis/docker-healthcheck

@@ -0,0 +1,4 @@
+#!/bin/bash
+set -eo pipefail
+
+[ "$(redis-cli ping)" = 'PONG' ]