title: Attempted to load class "DOMDocument" from the global namespace
body: <p>Ok so i have set up a new symfony3 project using :</p>
  
  <p>Vagrant----Virtualbox----PHP56----MYSQL55----UBUNTUTRUSTY64.</p>
  
  <p>Everything was working correctly until i make a "composer update". I have this error message and i cannot do anything now</p>
  
  <blockquote>
    <p>Attempted to load class "DOMDocument" from the global namespace</p>
  </blockquote>
  
  <p>So i found some proposed solution like "install php-xml" but it is already installed with newest version.</p>
  
  <p>Does anyone have a solution or guide me to the right direction to find one</p>
  
  <p>Many thanks </p>
  
  <p>Nico</p>