Gracefully shutdown on both SIGINT + SIGTERM

Most service managers (systemd, docker, etc) use SIGTERM as the shutdown signal by default rather than SIGINT (which is used for interactive CTRL-C).

index.mjs

@@ -99,8 +99,11 @@ const server = app.listen(port, () => {
 });
 
 // graceful shutdown
-process.on('SIGINT', () => {
+const gracefulShutdown = () => {
 	server.close(() => {
 		console.log('Server closed');
 	});
-});
+};
+
+process.on('SIGINT', gracefulShutdown);
+process.on('SIGTERM', gracefulShutdown);