Implemented privacy API (null_provider)

classes/privacy/provider.php

@@ -0,0 +1,40 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Privacy Subsystem implementation for mod_choicegroup.
+ *
+ * @package    mod_choicegroup
+ * @copyright  2018 Nicolas Dunand
+ * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+namespace mod_choicegroup\privacy;
+
+defined('MOODLE_INTERNAL') || die();
+
+class provider implements \core_privacy\local\metadata\null_provider {
+
+    /**
+     * Get the language string identifier with the component's language
+     * file to explain why this plugin stores no data.
+     *
+     * @return  string
+     */
+    public static function get_reason() : string {
+        return 'privacy:metadata';
+    }
+}

lang/en/choicegroup.php

@@ -152,5 +152,6 @@
 $string['collapse_all_groupings'] = 'Collapse All Groupings';
 $string['double_click_grouping_legend'] = 'Double click on a grouping to expand/collapse individually.';
 $string['double_click_group_legend'] = 'Double click on a group to add it.';
+$string['privacy:metadata'] = 'The Group Choice plugin does not store any personal data. All user data is stored by the group component of Moodle core (core_group).';