title: Lumen error on 'php artisan serve' command
body: <p>I have installed Lumen using composer command. I'm getting an error while starting the server, the command is <code>php artisan serve</code></p>
  
  <p>Error:</p>
  
  <pre><code>[Symfony\Component\Debug\Exception\FatalErrorException]  
  Class 'Memcached' not found
  </code></pre>
  
  <p>I have installed Memcached still, it's not working.</p>