title: How to change CakePHP 3.x validation error message
body: <p>Here is validation function in CakePHP 3.x for <code>PostsTable</code>:</p>
  
  <pre><code>public function validationDefault(Validator $validator)
  {
      $validator
          -&gt;add('id', 'valid', ['rule' =&gt; 'numeric'])
          -&gt;allowEmpty('id', 'create');
  
      $validator
          -&gt;requirePresence('title', 'create')
          -&gt;notEmpty('title','Please fill Title field');
  
      $validator
          -&gt;requirePresence('content', 'create')
          -&gt;notEmpty('content','Please add a Content');
  
      return $validator;
  }
  </code></pre>
  
  <p>The form in <code>add</code> view is:</p>
  
  <pre><code>&lt;?= $this-&gt;Form-&gt;create($post) ?&gt;
  &lt;fieldset&gt;
      &lt;legend&gt;&lt;?= __('Add Post') ?&gt;&lt;/legend&gt;
      &lt;?php
          echo $this-&gt;Form-&gt;input('title');
          echo $this-&gt;Form-&gt;input('content');
          echo $this-&gt;Form-&gt;input('category_id', ['options' =&gt; $categories]);
      ?&gt;
  &lt;/fieldset&gt;
  &lt;?= $this-&gt;Form-&gt;button(__('Submit')) ?&gt;
  &lt;?= $this-&gt;Form-&gt;end() ?&gt;
  </code></pre>
  
  <p>Why is the default validation message always shown instead of the <code>notEmpty</code> message? </p>