title: Phusion Passenger is currently not serving any applications
body: <p>I got error like <code>Phusion Passenger is currently not serving any applications.
  </code> while trying to restart passenger with <code>passenger-config restart-app</code> command.</p>
  
  <p>I googled but most of the answers were only related with deployment.</p>
  
  <p>I want to restart passenger in the development environment  as I am using vhost. 
  PS. My web server is nginx.</p>