title: 504 gateway timeout when using sync rather than database
body: <p>My problem is about using Supervisor as my worker what happens is when I upload my csv (users data) it will make a job that will shoot email until all the users in the csv are imported to the database. if I'm using <code>QUEUE_CONNECTION=database</code> and run the <code>php artisan queue:work</code> manually I don't have problems running or uploading the csv but when I change the <code>QUEUE_CONNECTION=sync</code> to run with the Supervisor I got this weird 504 Gateway Error on uploading the CSV.</p>