public function source()
    {
        $maps = Map::all();
        $arr = [];

        foreach($maps as $map) {
            $arr['markers'][] = [
                'title' => $map->article->short_title_english,
                'lat' => $map->latitude,
                'lng' => $map->longitude,
                'description' => $map->description_english,
                'status' => $map->status,
                'icon' => $map->icon
            ];
        }
        echo json_encode($arr);
    }