Add first draft of the user api

app/Api/Auth.php

@@ -0,0 +1,40 @@
+<?php
+
+namespace Api;
+
+use JsonRPC\AuthenticationFailure;
+use Symfony\Component\EventDispatcher\Event;
+
+/**
+ * Base class
+ *
+ * @package  api
+ * @author   Frederic Guillot
+ */
+class Auth extends Base
+{
+    /**
+     * Check api credentials
+     *
+     * @access public
+     * @param  string  $username
+     * @param  string  $password
+     * @param  string  $class
+     * @param  string  $method
+     */
+    public function checkCredentials($username, $password, $class, $method)
+    {
+        $this->container['dispatcher']->dispatch('api.bootstrap', new Event);
+
+        if ($username !== 'jsonrpc' && $this->authentication->authenticate($username, $password)) {
+            $this->checkProcedurePermission(true, $method);
+            $this->userSession->refresh($this->user->getByUsername($username));
+        }
+        else if ($username === 'jsonrpc' && $password === $this->config->get('api_token')) {
+            $this->checkProcedurePermission(false, $method);
+        }
+        else {
+            throw new AuthenticationFailure('Wrong credentials');
+        }
+    }
+}