title: changing attribute value on validation class in laravel
body: <p>How can we change attribute values on validation classes in laravel ?
  consider this code:</p>
  <pre><code>class Twice implements Rule
  { 
    public function passes($attribute, $value)
      {
          $value = $value * 2;
          return $value &gt; 20;
      }
  }
  </code></pre>
  <p>and now we receive value multiply by 2 in score attribute:</p>
  <pre><code>$rules = [
  'score' =&gt; [new Twice]
  ]
  </code></pre>
  <p>if we can't, what is your suggestion ?</p>