public function saveCircleToDatabase(Request $request)
 {
     $lat = $request->input('lat');
     $lng = $request->input('lng');
     $radius = $request->input('radius');
     $id = $request->input('id');
     $type = $request->input('type');
     if ($type === 'node') {
         $result = Node::add($lat, $lng, $radius, $id);
     } else {
         if ($type == 'poi') {
             $result = Point_of_interest::add($lat, $lng, $radius, $id);
         }
     }
     if ($result) {
         return response()->json(array('status' => 1, 'message' => 'Success'));
     }
     return response()->json(array('status' => 0, 'message' => 'Error !!'));
 }