Create a test file for each of the koan modules

test/koans/tasks_koans_test.exs

@@ -0,0 +1,17 @@
+defmodule TasksTests do
+  use ExUnit.Case
+  use TestHarness
+
+  test "Tasks" do
+    answers = [
+      10,
+      :ok,
+      nil,
+      false,
+      9,
+      [1,4,9,16]
+      ]
+
+    test_all(Tasks, answers)
+  end
+end