Fix the Archive Link

[jendiamond]

The link in the side bar "ARCHIVES" should go to a page where all the posts are listed. Right now it is broken. The error is:

NameError at /archives  
undefined local variable or method `article_months' for #<Nesta::App:0x00000003640318>
file: app.rb location: archive_by_month line: 88

---

app.rb

  def archive_by_month
    article_months.each do |month_name|
      haml_tag :li do
        haml_tag :a, :id => "#{month_name}"
        haml_tag :h2, month
        haml_tag :ol do
          articles = Page.find_articles.select { |a| a.date.month == month }
          list_articles(articles)
        end
      end
    end
  end