protected function synchronizeUser()
 {
     $alwaysUpdate = $this->option('force-update');
     $this->progressbar = $this->getHelperSet()->get('progress');
     $this->progressbar->start($this->output, User::count());
     User::chunk(500, function ($users) use($alwaysUpdate) {
         foreach ($users as $user) {
             $this->progressbar->advance();
             $email = $user->email;
             MailChimpIntegration::syncMemberToMailChimp($email, $user, false);
         }
     });
     ${$this}->progressbar->finish();
 }