fix: listen on ipv4 by default. May prevent issues on VPS with ipv6 e…

…nabled

backend/bin/www

@@ -26,7 +26,7 @@ var server = http.createServer(app);
  * Listen on provided port, on all network interfaces.
  */
 
-server.listen(port);
+server.listen(port, process.env.LISTEN_ADDRESS || "0.0.0.0");
 server.on("error", onError);
 server.on("listening", onListening);