fixup! revert removal of require in doc

Author: pirj

features/directory_structure.feature

@@ -151,6 +151,8 @@ Feature: Directory Structure
   Scenario: Non-rails related specs do not require `:type` metadata by default
     Given a file named "spec/ledger/entry_spec.rb" with:
       """ruby
+      require "spec_helper"
+
       Entry = Struct.new(:description, :us_cents)
 
       RSpec.describe Entry do