Add ordering ex

ordering.sc

@@ -0,0 +1,22 @@
+import scala.math.Ordering.IntOrdering
+
+
+// Define instantiable integer orderings
+class RealIntOrdering extends IntOrdering {}
+
+class ReverseIntOrdering extends Ordering[Int] {
+  val realIntOrdering = new RealIntOrdering()
+  def compare(x: Int, y: Int): Int = -realIntOrdering.compare(x, y)
+}
+
+
+// Test stuff
+val values = List(1,2,6,3,4)
+
+val ord: Ordering[Int] = new RealIntOrdering()
+values.min(cmp = ord)
+values.sorted(ord = ord)
+
+val reverseOrd = new ReverseIntOrdering()
+values.min(cmp = reverseOrd)
+values.sorted(ord = reverseOrd)