public static function map($file_id, $params)
 {
     $dm = new DocumentMapping();
     $dm->owner_id = $params["owner_id"];
     $dm->owner_type = $params["owner_type"];
     $dm->file_id = $file_id;
     $dm->document_type = $params["proof_type"];
     var_dump($params);
     die;
     $dm->save();
 }