Remove the City constructor

The City from the AirlineService doesn't have a constructor.

Plattform/Plattform/Helper/GenerateData.cs

@@ -28,7 +28,12 @@ namespace Plattform.Helper
         {
             foreach (var item in ListCities)
             {
-                Cities.Add(new City(item, 3300));
+                Cities.Add(new City
+                {
+                   Name = item,
+                   ZipCode = 3300
+                }
+                );
             }
             return Cities;
         }