title: LogIn in Controller with FOSUserBundle
body: <p>I'm working on a project where User can log in with a certificate.</p>
  
  <p>So if there is a valid certificate in a POST request I want to login the user in a controller and redirect to the home site.</p>
  
  <p>I'm using the FOSUserBundle but did not found anything that explains whether this is possible or how it's done.</p>
  
  <p>Did anybody already did this or has a idea how it could be done?</p>