Add project files.

MonkeyFinder/MonkeyContext.cs

@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Text.Json.Serialization;
+using System.Threading.Tasks;
+
+namespace MonkeyFinder
+{
+    [JsonSerializable(typeof(List<Monkey>))]
+    internal sealed partial class MonkeyContext : JsonSerializerContext
+    {
+
+    }
+}