Add forgot password feature

app/Controller/Captcha.php

@@ -0,0 +1,29 @@
+<?php
+
+namespace Kanboard\Controller;
+
+use Gregwar\Captcha\CaptchaBuilder;
+
+/**
+ * Captcha Controller
+ *
+ * @package controller
+ * @author  Frederic Guillot
+ */
+class Captcha extends Base
+{
+    /**
+     * Display captcha image
+     *
+     * @access public
+     */
+    public function image()
+    {
+        $this->response->contentType('image/jpeg');
+
+        $builder = new CaptchaBuilder;
+        $builder->build();
+        $this->sessionStorage->captcha = $builder->getPhrase();
+        $builder->output();
+    }
+}