🩹 Fix #38

Sources/Model/IManager.cs

@@ -1,15 +1,12 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
-
+using System.Collections.Generic;
 namespace Model
 {
     internal interface IManager
     {
         public T Add<T>(ref T toAdd);
-        public T Remove<T>(ref T toRemove);
+        public void Remove<T>(ref T toRemove);
         public T Update<T>(ref T before, ref T after);
+        public T GetOneById<T>(int id);
+        public IEnumerable<T> GetAll<T>();
     }
 }