Add auditable properties to BaseDomainModel.

EntityFrameworkCore.Domain/BaseDomainModel.cs

@@ -4,4 +4,7 @@ public abstract class BaseDomainModel
 {
   public int Id { get; set; } // Anything called "Id" is automatically a Primary Key.
   public DateTime CreatedDate { get; set;}
+  public DateTime ModifiedDate { get; set;}
+  public string CreatedBy { get; set; }
+  public string ModifiedBy { get; set; }
 }