accumulate: add bookkeeping (#489)

Add the bookkeeping module to accumulate_test.rb
Add bookkeeping to example.rb

exercises/accumulate/accumulate_test.rb

@@ -45,4 +45,25 @@ def test_do_not_change_in_place
     original.accumulate { |n| n * n }
     assert_equal copy, original
   end
+
+  # Problems in exercism evolve over time, as we find better ways to ask
+  # questions.
+  # The version number refers to the version of the problem you solved,
+  # not your solution.
+  #
+  # Define a constant named VERSION inside of the top level BookKeeping
+  # module.
+  #  In your file, it will look like this:
+  #
+  # module BookKeeping
+  #   VERSION = 1 # Where the version number matches the one in the test.
+  # end
+  #
+  # If you are curious, read more about constants on RubyDoc:
+  # http://ruby-doc.org/docs/ruby-doc-bundle/UsersGuide/rg/constants.html
+
+  def test_bookkeeping
+    skip
+    assert_equal 1, BookKeeping::VERSION
+  end
 end

exercises/accumulate/example.rb

@@ -1,3 +1,7 @@
+module BookKeeping
+  VERSION = 1
+end
+
 class Array
   def accumulate
     result = []