title: mysqli is a not known class in a symfony controller
body: <p>I decide to work with <code>Symfony</code> for three weeks, realizing a small projekt to test.
  Inside a Controller I use MySQL native without Problems. Now I want to change to MySQLi and nothing runs.</p>
  
  <p>Connecting to the DB with: </p>
  
  <pre><code>$mysqliName = new mysqli('localhost', 'user', 'psasswd,', 'database');
  </code></pre>
  
  <p>fails with:</p>
  
  <pre><code>"Class 'blabla\HaloBundle\Controller\mysqli' not found in /Applications/MAM.../HaloController.php"
  </code></pre>
  
  <p>I can run MySQL in a "normal" php, out of Symfony without problems. What must I do, that I can use the MySQLi Classes in a Controller?</p>