title: Laravel Regex Validation does not work
body: <p>I want to define the username as <strong>4 letters + 4 digits</strong> like "<code>abcd1234</code>". Here is my code in Laravel 5:</p>
  
  <pre><code>    public function rules()
      {
          return [
              'username' =&gt; 'required|regex:/^[A-Za-z]{4}\d{4}$/|unique:users',
              'email' =&gt; 'required|email|unique:users',
              'password' =&gt; 'required|confirmed|min:8'
          ];
      }
  </code></pre>
  
  <p>However, the regex validation does not work at all. How to solve this problem? Thanks!</p>