Add new API procedures for groups, roles and project permissions

app/Api/GroupMember.php

@@ -0,0 +1,32 @@
+<?php
+
+namespace Kanboard\Api;
+
+/**
+ * Group Member API controller
+ *
+ * @package  api
+ * @author   Frederic Guillot
+ */
+class GroupMember extends \Kanboard\Core\Base
+{
+    public function getGroupMembers($group_id)
+    {
+        return $this->groupMember->getMembers($group_id);
+    }
+
+    public function addGroupMember($group_id, $user_id)
+    {
+        return $this->groupMember->addUser($group_id, $user_id);
+    }
+
+    public function removeGroupMember($group_id, $user_id)
+    {
+        return $this->groupMember->removeUser($group_id, $user_id);
+    }
+
+    public function isGroupMember($group_id, $user_id)
+    {
+        return $this->groupMember->isMember($group_id, $user_id);
+    }
+}