title: Use Twig Extension in controller
body: <p>I have a slugify method in an Twig Extension which i would like to use in some cases in a controller, f.e with redirects.<br>
  Is there an easy way for this?<br>
  How could i access functions from Twig Extensions in the controller?</p>
  
  <p>Or do i have to make the slugify method somewere as a helper in order to use it in the code and in twig?</p>