title: passport.authenticate() in routing-controllers framework
body: <p>I am new to JavaScript/TypeScript development, and I am currently extending an express application with an Single-Sign-On login. The express app uses routing-controllers framework to handle requests and should use passport-saml for authentication.
  I have already managed to get the authentication working with standard express routes:</p>
  
  <pre><code>export class SsoRoutes {
      public router: Router;
  
      constructor() {
          this.router = Router();
      }
  
  
      this.router.get('/login-sso', passport.authenticate('saml'));
  
      this.router.post('/login-sso/consume', passport.authenticate('saml', {
          failureRedirect: '/',
          failureFlash: true,
          session: false
      }), function (req, res) {
          // handle callback
  
      });
  }
  </code></pre>
  
  <p>But I can not figure out how to use the <code>passport.authenticate(...)</code> method within the routing-controllers framework. 
  Can someone explain this to me?</p>