code: function addGroup(group, options) {
    options = _.opts(options, {gid: null});
    if (!runningAsRoot()) return;
    if (!group) throw new Error('You must provide a group');
    if (groupExists(group)) {
      return;
    }
  
    if (isPlatform('linux')) {
      _addGroupLinux(group, options);
    } else if (isPlatform('osx')) {
      _addGroupOsx(group, options);
    } else if (isPlatform('windows')) {
      throw new Error(`Don't know how to add group ${group} on Windows`);
    } else {
      throw new Error(`Don't know how to add group ${group} in current platform`);
    }
  }
docs: Add a group to the system
  @function $os~addGroup
  @param {string} group - Groupname
  @param {Object} [options]
  @param {string|number} [options.gid=null] - Group ID
  @example
  // Creates group 'mysql'
  $os.addGroup('mysql');