code: func NewConfig(files []string, prefix string, tag string) Config {
  	var config *config
  	// Files can be given colon-separated
  	expandedFiles := []string{}
  	for _, f := range files {
  		expandedFiles = append(expandedFiles, strings.Split(f, ":")...)
  	}
  	configPath := findConfigPath(expandedFiles)
  	config = readConfig(configPath, expandedFiles)
  	config.path = configPath
  	config.initialize(prefix)
  	config.validate()
  	config.tag = tag
  	milliseconds := time.Now().UnixNano() / 1000000
  	config.uniqueID = strconv.FormatInt(milliseconds, 10)
  	return config
  }
docs: // NewConfig retus a new config based on given
  // location.
  // Containers will be ordered so that they can be
  // brought up and down with Docker.