code: public int tag(String image, String repository, String tag, boolean force) throws DockerException {
  		Preconditions.checkNotNull(image, "image was not specified");
  		Preconditions.checkNotNull(repository, "repository was not specified");
  		Preconditions.checkNotNull(tag, " tag was not provided");
  
  		MultivaluedMap<String, String> params = new MultivaluedMapImpl();
  		params.add("repo", repository);
  		params.add("tag", tag);
  		params.add("force", String.valueOf(force));
  
  		WebResource webResource = client.resource(restEndpointUrl + "/images/" + image + "/tag").queryParams(params);
  	    
  		try {
  			LOGGER.trace("POST: {}", webResource);
  			ClientResponse resp = webResource.post(ClientResponse.class);
  			return resp.getStatus();
  		} catch (UniformInterfaceException exception) {
  			throw new DockerException(exception);
  		}
  	}
docs: Tag an image into a repository
  
  @param image       the local image to tag (either a name or an id)
  @param repository  the repository to tag in
  @param tag         any tag for this image
  @param force       (not documented)
  @return the HTTP status code (201 for success)