public void ChangeDepartmentOrShift(Department department, [Optionally] Shift shift)
{
CurrentAssignment().EndDate = DateTime.Now;
var newAssignment = Container.NewTransientInstance <EmployeeDepartmentHistory>();
newAssignment.Department = department;
newAssignment.Shift = shift;
newAssignment.Employee = this;
newAssignment.StartDate = DateTime.Now;
Container.Persist(ref newAssignment);
DepartmentHistory.Add(newAssignment);
}
