title: Guzzle Http not found mailgun
body: <p>I'm trying to use Mailgun in my php project.
  I've installed all the necessary components:</p>
  
  <ul>
  <li>Composer</li>
  <li>Guzzle 6</li>
  </ul>
  
  <p>This is my PHP code to test the e-mail service:</p>
  
  <pre><code>require 'vendor/autoload.php';
  ini_set('display_errors', 'On');
  $client = new \Http\Adapter\Guzzle6\Client();
  
  define('MAILGUN_KEY', 'key-xxxxxxxxxx');
  define('MAILGUN_DOMAIN', 'my-domain.nl');
  
  $mailgun = new \Mailgun\Mailgun(MAILGUN_KEY, $client);
  
  $mailgun-&gt;sendMessage(MAILGUN_DOMAIN, [
              'from'      =&gt; 'my@email.com',
              'to'        =&gt; 'your@e-mail.com',
              'subject'   =&gt; 'This is a test e-mail',
              'html'      =&gt; "
                  Hello,&lt;/br&gt;&lt;/br&gt;
                  This is a test." 
          ]);
  </code></pre>
  
  <p>It still throws the following error:</p>
  
  <pre><code>Fatal error: Class 'Http\Adapter\Guzzle6\Client' not found
  </code></pre>
  
  <p>Why is it still unable to find Guzzle6 while it is installed and required in composer.json?</p>
  
  <p>EDIT:</p>
  
  <p>Maybe some important information, I have installed composer and Guzzle in /usr/local/lib and made it globally available. Should i do it this way or install those in the root folder of my domain?</p>