change number of queue processors

server/queues/queues.js

@@ -12,7 +12,7 @@ const redis = {
 
 const visit = new Queue("visit", { redis });
 visit.clean(5000, "completed");
-visit.process(8, path.resolve(__dirname, "visit.js"));
+visit.process(6, path.resolve(__dirname, "visit.js"));
 visit.on("completed", job => job.remove());
 
 // TODO: handler error