code: func dispatchVolume(d dispatchRequest, c *instructions.VolumeCommand) error {
  	if d.state.runConfig.Volumes == nil {
  		d.state.runConfig.Volumes = map[string]struct{}{}
  	}
  	for _, v := range c.Volumes {
  		if v == "" {
  			return errors.New("VOLUME specified can not be an empty string")
  		}
  		d.state.runConfig.Volumes[v] = struct{}{}
  	}
  	return d.builder.commit(d.state, fmt.Sprintf("VOLUME %v", c.Volumes))
  }
docs: // VOLUME /foo
  //
  // Expose the volume /foo for use. Will also accept the JSON array form.
  //