Added swap example to parallel assignments

src/about_array_assignment.rb

@@ -35,4 +35,11 @@ class AboutArrayAssignment < EdgeCase::Koan
     assert_equal __("John"), first_name
   end
 
+  def test_swapping_with_parallel_assignment
+    first_name = "Roy"
+    last_name = "Rob"
+    first_name, last_name = last_name, first_name
+    assert_equal __('Rob'), first_name
+    assert_equal __('Roy'), last_name
+  end
 end