/// <summary>
 /// Initializes a new instance of the <see cref="PromotionManager"/> class.
 /// </summary>
 /// <param name="engine">The engine<see cref="IndustryEngine"/>.</param>
 public PromotionManager(IndustryEngine engine)
 {
     _engine    = engine;
     Promotions = new List <Promotion>();
     Init();
 }
 /// <summary>
 /// Initializes a new instance of the <see cref="ProductManager"/> class.
 /// </summary>
 /// <param name="engine">The engine<see cref="IndustryEngine"/>.</param>
 public ProductManager(IndustryEngine engine)
 {
     _engine = engine;
     Init();
 }