Use data model when adding a new item

Use the data model instead of a primitive to allow further options to be developed later on.

src/Todo.CLI/Handlers/AddCommandHandler.cs

@@ -4,6 +4,7 @@
 using System.IO;
 using System.Reflection;
 using Todo.Core;
+using Todo.Core.Model;
 
 namespace Todo.CLI.Handlers
 {
@@ -14,7 +15,10 @@ public static ICommandHandler Create(IServiceProvider serviceProvider)
             return CommandHandler.Create<string>(async (subject) =>
             {
                 var todoItemRepository = (ITodoItemRepository)serviceProvider.GetService(typeof(ITodoItemRepository));
-                await todoItemRepository.AddAsync(subject);
+                await todoItemRepository.AddAsync(new TodoItem()
+                {
+                    Subject = subject
+                });
             });
         }
     }

src/Todo.Core/Repository/ITodoItemRepository.cs

@@ -9,7 +9,7 @@ namespace Todo.Core
 {
     public interface ITodoItemRepository
     {
-        Task AddAsync(string subject);
+        Task AddAsync(TodoItem item);
         Task<IEnumerable<TodoItem>> ListAsync(bool listAll);
     }
 }

src/Todo.Core/Repository/TodoItemRepository.cs

@@ -16,12 +16,12 @@ public TodoItemRepository(IAuthenticationProvider authenticationProvider)
         {
         }
 
-        public async Task AddAsync(string subject)
+        public async Task AddAsync(TodoItem item)
         {
             var graphServiceClient = new GraphServiceClient(AuthenticationProvider);
             await graphServiceClient.Me.Outlook.Tasks.Request().AddAsync(new OutlookTask()
             {
-                Subject = subject
+                Subject = item.Subject
             });
         }