title: Method validate does not exist - Laravel 5.4
body: <p>I have a very weird problem. When I'm submitting the form, it throws an error with server-side validation.</p>
  
  <p>Here is my simple controller:</p>
  
  <pre><code>namespace App\Http\Controllers;
  
  use Newsletter;
  use Illuminate\Http\Request;
  
  class SubscriptionController extends Controller
  {
      public function subscribe(Request $request)
      {
          $request-&gt;validate([
              'email' =&gt; 'required|email',
              ]);
      }
  }
  </code></pre>
  
  <p>Submitting the form gives me:</p>
  
  <blockquote>
    <p>BadMethodCallException
    Method validate does not exist.</p>
  </blockquote>
  
  <p>it should work according to:</p>
  
  <p><a href="https://laravel.com/docs/5.4/validation" rel="noreferrer">https://laravel.com/docs/5.4/validation</a></p>