added deployment file

docker/healthcheck.php

@@ -0,0 +1,11 @@
+<?php
+// Check Apache + PHP + database readiness without requiring curl in the image.
+$socket = @fsockopen('127.0.0.1', 80, $errno, $error, 3);
+if (!$socket) {
+    exit(1);
+}
+stream_set_timeout($socket, 3);
+fwrite($socket, "GET /healthz HTTP/1.0\r\nHost: localhost\r\nConnection: close\r\n\r\n");
+$status = fgets($socket);
+fclose($socket);
+exit(is_string($status) && preg_match('/^HTTP\/\d\.\d 200\b/', $status) ? 0 : 1);