build: 🔨 Docker setup

Dockerfile, docker-compose and entrypoint

entrypoint.dev.sh

@@ -0,0 +1,10 @@
+#!/bin/sh
+
+set -e
+echo "Environment: $RAILS_ENV"
+
+bundle check || bundle install --jobs 20 --retry 5
+
+rm -f $APP_PATH/tmp/pids/server.pid
+
+${@}