Created Generations Class

Added Generations to track the generations of Poke`mon, and pick random based upon unlocked level of Generation.

Library/Singletons/Generations.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Collections.Generic;
+
+namespace PokePurple.Library.Singletons;
+
+public class Generations
+{
+    private List<Range> _generations =
+    [
+        new Range(1,151),
+        new Range(152, 251),
+        new Range(252, 386),
+        new Range(387, 493),
+        new Range(494, 649),
+        new Range(650, 721),
+        new Range(722, 809),
+        new Range(810, 905),
+        new Range(906, 1025)
+    ];
+
+    public int Generation = 1;
+
+    public int PickRandomPokemon()
+    {
+        var maxRange = _generations[Generation].End.Value;
+        var random = new Random();
+        var id = random.Next(1, maxRange);
+        return id;
+    }
+}