title: CakePHP 3 and form validation errors
body: <p>I use cakePHP 3 and I have a sign in form with Form->input().
  If on purpose I make an error, this error doesn't whow up under the Form field. It doesn't appear anywhere.</p>
  
  <p>My code is like this:</p>
  
  <pre><code>    $newUser = $this-&gt;Users-&gt;newEntity($this-&gt;request-&gt;data());
  
      if (!$this-&gt;Users-&gt;save($newUser)) {
          debug($newUser-&gt;errors());
          $this-&gt;Flash-&gt;error('Error');
          return;
      }
  </code></pre>
  
  <p>Debug show the errors, but shouldn't they appear under each form element automatically?</p>