code: func (d EnhancedArchive) Add(name, path string) error {
  	name = strings.Replace(filepath.Join(d.wrap, name), "\\", "/", -1)
  	log.Debugf("adding file: %s as %s", path, name)
  	if _, ok := d.files[name]; ok {
  		return fmt.Errorf("file %s already exists in the archive", name)
  	}
  	d.files[name] = path
  	return d.a.Add(name, path)
  }
docs: // Add adds a file