[Add] Implementation of TutorController class

LangLang/Core/Controller/TutorController.cs

@@ -0,0 +1,37 @@
+using LangLang.Core.DAO;
+using LangLang.Core.Model;
+using LangLang.Core.Observer;
+using System.Collections.Generic;
+
+namespace LangLang.Core.Controller
+{
+    public class TutorController
+    {
+        private readonly TutorDAO _tutors;
+
+        public TutorController()
+        {
+            _tutors = new TutorDAO();
+        }
+
+        public Dictionary<int, Tutor> GetAllTutors()
+        {
+            return _tutors.GetAllTutors();
+        }
+
+        public void Add(Tutor tutor)
+        {
+            _tutors.Add(tutor);
+        }
+
+        public void Delete(int tutorId)
+        {
+            _tutors.Remove(tutorId);
+        }
+
+        public void Subscribe(IObserver observer)
+        {
+            _tutors.Subscribe(observer);
+        }
+    }
+}