Added mail provider class

app/ServiceProvider/MailProvider.php

@@ -0,0 +1,34 @@
+<?php
+
+namespace Kanboard\ServiceProvider;
+
+use Kanboard\Core\Mail\Client as EmailClient;
+use Pimple\Container;
+use Pimple\ServiceProviderInterface;
+
+/**
+ * Mail Provider
+ *
+ * @package Kanboard\ServiceProvider
+ * @author  Frederic Guillot
+ */
+class MailProvider implements ServiceProviderInterface
+{
+    /**
+     * Registers services on the given container.
+     *
+     * @param Container $container
+     */
+    public function register(Container $container)
+    {
+        $container['emailClient'] = function ($container) {
+            $mailer = new EmailClient($container);
+            $mailer->setTransport('smtp', '\Kanboard\Core\Mail\Transport\Smtp');
+            $mailer->setTransport('sendmail', '\Kanboard\Core\Mail\Transport\Sendmail');
+            $mailer->setTransport('mail', '\Kanboard\Core\Mail\Transport\Mail');
+            return $mailer;
+        };
+
+        return $container;
+    }
+}