допилил свои модели

Course/DataModels/Models/IMachineModel.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace DataModels.Models
+{
+    public interface IMachineModel : IId
+    {
+        string Title { get; }
+        string Country { get; }
+    }
+}

Course/DataModels/Models/IWorkerModel.cs

@@ -10,7 +10,7 @@ namespace DataModels.Models
     {
         string Name { get; }
         DateTime Birthday { get; }
-        String Specialization { get; }
-        Double Salary { get; }
+        string Specialization { get; }
+        double Salary { get; }
     }
 }

Course/DataModels/Models/IWorkshopModel.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace DataModels.Models
+{
+    public interface IWorkshopModel : IId
+    {
+        string Title { get; }
+        string Address { get; }
+        string Director { get; }
+    }
+}