Add health check.

Dockerfile

@@ -21,5 +21,10 @@ EXPOSE 3000
 # Set environment
 ENV NODE_ENV=production
 
+# add health check
+HEALTHCHECK --interval=30s --timeout=3s --retries=3 \
+  CMD wget -qO- http://localhost:3000/_healthz || exit 1
+
+
 # Start the SvelteKit app
 CMD ["node", "build"]

src/routes/_healthz/+server.js

@@ -0,0 +1,3 @@
+export const GET = () => {
+  return new Response('ok', { status: 200 });
+};