added lesson 6

src/Lesson6/Tuples.sc

@@ -0,0 +1,13 @@
+def merge(x: List[Int], y: List[Int]): List[Int] = {
+  (x, y) match {
+    case (list, Nil) => list
+    case (Nil, list) => list
+    case (e1::rest1, e2::rest2) =>
+      if (e1 < e2) e1::merge(rest1, y)
+      else e2::merge(x, rest2)
+  }
+}
+
+val n1 = List(0, 2, 4, 6)
+val n2 = List(1, 3, 5, 7)
+merge(n1, n2)