title: FOSUserBundle: How to know which users are online
body: <p>I'm using FOS Rest Bundle and I'd like to show which users are online in the website. I don't know (I couldn't find any info about it) if there's a way to query the database and get if a user is currently online or not.</p>
  
  <p>Is there a way to know this or any other bundle that could provide this info?</p>
  
  <p>Thanks in advance</p>