@Security.Authenticated(Secured.class)
 public static Result download() {
   User user = getCurrentUser();
   if (!user.isAdmin) return redirect(routes.Application.contacts());
   String filename = PoiExcelFileReader.writeFile(Contact.all());
   response().setContentType("application/x-download");
   String headerName = "Content-disposition";
   String headerValue = "attachment; filename=" + filename;
   response().setHeader(headerName, headerValue);
   return ok(new File(filename));
   // return redirect(routes.Application.contacts());
 }