Add spec for VersionHelpers module
user
```ruby
require 'spec_helper'
require 'ostruct'

module PaperTrailScrapbook
  ::RSpec.describe VersionHelpers do

    let(:person) do
      p = Person.new(name: 'The Tim Man')
      p.save!
      p
    end

    let(:book) do
      b = Book.new(title: 'How the Grinch stole Xmas')
      b.save!
      b
    end

    let(:version) do
      OpenStruct.new(event: 'create',
                     item_type: 'Book',
                     item_id: book.id,
                     created_at: DateTime.current,
                     version_author: person.id)
    end

    let(:config) { PaperTrailScrapbook.config }

    let(:subject) { JournalEntry.new(version) }

    before do
      PaperTrailScrapbook.config.whodunnit_class = Person
      PaperTrail.whodunnit = person.id
    end


    describe '#model' do
      it 'returns expected result' do
        expect(subject.model).to eql('Book')
      end
    end

    describe '#model_id' do
      it 'returns expected result' do
        expect(subject.model_id).to equal(book.id)
      end
    end

    describe '#create?' do
      it 'returns true if create event' do
        expect(subject.create?).to be true
      end

      it 'returns false if not create event' do
        version.event = 'update'

        expect(subject.create?).to be false
      end
    end

    describe '#changes' do
      it 'returns changes' do
        expect(subject.changes).to eql('')
      end
    end

    describe '#config' do
      it 'returns instance of Config' do
        expect(subject.config).to be_an_instance_of(PaperTrailScrapbook::Config)
      end
    end

    describe '#whenn' do
      it 'returns version created_at' do
        expect(subject.whenn)
            .to eql(version.created_at.strftime(config.time_format))
      end
    end

    describe '#kind' do
      it 'returns expected value' do
        expect(subject.kind).to eql('created')
      end
    end

    describe '#who' do
      it 'returns expected value' do
        expect(subject.who).to eql(person.name)
      end
    end

    describe '#whodunnit_class' do
      it 'returns expected value' do
        expect(subject.whodunnit_class).to eql(Person)
      end
    end
  end
end
```
assistant