public static function update($id)
 {
     self::check_admin_logged_in();
     $attributes = self::get_attributes();
     $attributes['id'] = $id;
     $competition = new Competition($attributes);
     $errors = $competition->errors();
     if (count($errors) > 0) {
         View::make('competition/edit.html', array('errors' => $errors, 'attributes' => $attributes));
     } else {
         $competition->update();
         Participant::nullify_and_update_competition_standings($id);
         Redirect::to('/competition/' . $competition->id, array('message' => 'Kilpailua muokattu onnistuneesti!'));
     }
 }