Expose to the user interface the email sender address

app/Core/Mail/Transport/Mail.php

@@ -32,7 +32,7 @@ class Mail extends Base implements ClientInterface
         try {
             $message = Swift_Message::newInstance()
                 ->setSubject($subject)
-                ->setFrom(array(MAIL_FROM => $author))
+                ->setFrom(array($this->helper->mail->getMailSenderAddress() => $author))
                 ->setBody($html, 'text/html')
                 ->setTo(array($email => $name));
 

app/Helper/MailHelper.php

@@ -45,4 +45,21 @@ class MailHelper extends Base
 
         return $subject;
     }
+
+    /**
+     * Get mail sender address
+     *
+     * @access public
+     * @return string
+     */
+    public function getMailSenderAddress()
+    {
+        $email = $this->configModel->get('mail_sender_address');
+
+        if (!empty($email)) {
+            return $email;
+        }
+
+        return MAIL_FROM;
+    }
 }

app/Template/config/application.php

@@ -9,6 +9,9 @@
     <?= $this->form->text('application_url', $values, $errors, array('placeholder="http://example.kanboard.net/"')) ?>
     <p class="form-help"><?= t('Example: http://example.kanboard.net/ (used to generate absolute URLs)') ?></p>
 
+    <?= $this->form->label(t('Email sender address'), 'mail_sender_address') ?>
+    <?= $this->form->text('mail_sender_address', $values, $errors, array('placeholder="'.MAIL_FROM.'"')) ?>
+
     <?= $this->form->label(t('Language'), 'application_language') ?>
     <?= $this->form->select('application_language', $languages, $values, $errors) ?>