code: func (a *Driver) Create(id, parent string, opts *graphdriver.CreateOpts) error {
  
  	if opts != nil && len(opts.StorageOpt) != 0 {
  		return fmt.Errorf("--storage-opt is not supported for aufs")
  	}
  
  	if err := a.createDirsFor(id); err != nil {
  		return err
  	}
  	// Write the layers metadata
  	f, err := os.Create(path.Join(a.rootPath(), "layers", id))
  	if err != nil {
  		return err
  	}
  	defer f.Close()
  
  	if parent != "" {
  		ids, err := getParentIDs(a.rootPath(), parent)
  		if err != nil {
  			return err
  		}
  
  		if _, err := fmt.Fprintln(f, parent); err != nil {
  			return err
  		}
  		for _, i := range ids {
  			if _, err := fmt.Fprintln(f, i); err != nil {
  				return err
  			}
  		}
  	}
  
  	return nil
  }
docs: // Create three folders for each id
  // mnt, layers, and diff