title: TYPO3 Extbase - Does Dependency Injection work in Service Classes?
body: <p>I'm using a Service of type auth for adding an API based login.
  I tried to add a User with the FrontendUserRepository of Extbase via <code>@inject</code>.
  But this doesn't work.</p>
  
  <p>Am i doing something wrong or is this to early to use the Dependency Injection?</p>
  
  <p>P.S.: I know i can use the repository the following way:</p>
  
  <pre><code>$objectManager = GeneralUtility::makeInstance('TYPO3\CMS\Extbase\Object\ObjectManager');
  $this-&gt;frontendUserRepository = $objectManager-&gt;get('TYPO3\\CMS\\Extbase\\Domain\\Repository\\FrontendUserRepository');
  </code></pre>