title: laravel Interface 'JsonSerializable' not found
body: <p>Im using the following for my application for social media login
  <a href="https://github.com/madewithlove/laravel-oauth2" rel="nofollow">https://github.com/madewithlove/laravel-oauth2</a></p>
  
  <p>but im getting this error</p>
  
  <pre><code>Symfony \ Component \ Debug \ Exception \ FatalErrorException
  Interface 'JsonSerializable' not found
  open: /Applications/AMPPS/www/docsearch/vendor/madewithlove/laravel-oauth2/src/OAuth2/Token/Access.php
   * @package    OAuth2
   * @category   Token
   * @author     Phil Sturgeon
   * @copyright  (c) 2011 HappyNinjas Ltd
   */
  
  class Token_Access extends Token implements \JsonSerializable
  {
      /**
       * @var  string  access_token
  </code></pre>