code: function ContactsGroupsPermissionsUpdate(options, groupId, username) {
      ActionAbstract.call(this, options);
      this._groupId = groupId;
      this._username = username;
  }
docs: update permissions
  @see  http://dev.smsapi.pl/#!/contacts%2Fgroups/edit_0
  @param {Object} options
  @param {String} groupId
  @param {String} username
  @extends ActionAbstract
  @constructor