/*
 * How to call:
  AddProjectUser("userAdd", "QATester");
 */
private void AddProjectUser(String newProjectUser, String addToUserGroup)
{
  ICustomization objCust = (ICustomization)tdConnection.Customization;

  ICustomizationUsers objUsers = (ICustomizationUsers)objCust.Users;
  objUsers.AddUser(newProjectUser);

  ICustomizationUsersGroups objUsersGroups = (ICustomizationUsersGroups)objCust.UsersGroups;
  ICustomizationUsersGroup objUsersGroup = (ICustomizationUsersGroup)objUsersGroups.Group[addToUserGroup];
  objUsersGroup.AddUser(newProjectUser);

  objCust.Commit();
}