/**
  * Validate before save
  *
  * @param ValidationErrors $errors
  */
 function validate(ValidationErrors &$errors)
 {
     parent::validate($errors);
     if ($this->validatePresenceOf('custom_field_1')) {
         if ($this->getCustomField1() < 0 || $this->getCustomField1() > 100) {
             $errors->addError(lang('Percent complete value must be between 0 and 100'), 'custom_field_1');
         }
     }
 }