Lots of work for chapters. This code will be refactored in a chapter rewrite.

API/Comparators/ChapterSortComparer.cs

@@ -0,0 +1,18 @@
+using System.Collections.Generic;
+
+namespace API.Comparators
+{
+    public class ChapterSortComparer : IComparer<int>
+    {
+        public int Compare(int x, int y)
+        {
+            if (x == 0 && y == 0) return 0;
+            // if x is 0, it comes second
+            if (x == 0) return 1;
+            // if y is 0, it comes second
+            if (y == 0) return -1;
+
+            return x.CompareTo(y);
+        }
+    }
+}