/// <summary> Adds a user to the list of users which belong to this user group </summary>
 /// <param name="User"> Small user object which holds the very basic information about this user </param>
 internal void Add_User(User_Group_Member User)
 {
     users.Add(User);
 }
 /// <summary> Adds a user to the list of users which belong to this user group </summary>
 /// <param name="User"> Small user object which holds the very basic information about this user </param>
 internal void Add_User(User_Group_Member User)
 {
     users.Add(User);
 }