code: public static function getDropdownMap($keyAttribute, $valueAttribute, array $default = [])
      {
          $map = ArrayHelper::map(self::getActive(), $keyAttribute, $valueAttribute);
          if ($default) {
              $map = array_merge($default, $map);
          }
  
          return $map;
      }
docs: Fetch dropdown data for model
  
  Usage
  <code>
  // with default
  FormCategory::getDropdownMap('key', 'name', ['' => 'Select Category'])
  
  // without default
  FormCategory::getDropdownMap('key', 'name')
  </code>
  @author Adeyemi Olaoye <yemi@cottacush.com>
  @param $keyAttribute
  @param $valueAttribute
  @param array $default
  an array map of the value to the labels
  @return array