Paginating categories in middleman blog

config.rb

# In config.rb
def get_locals(category, total_pages, i, articles, total_articles)
  prev_page = false

  # Is the a previous page and if so what does it look like
  if (i - 1) == 1
    prev_page = "/blog/categories/#{category}"
  elsif (i - 1) > 1
    prev_page = "/blog/categories/#{category}/page/#{i-1}"
  end

  # Return the local variables
  {
    page_articles:  articles,
    paginate:       total_pages > 1,
    category:       category,
    page_number:    i,
    num_pages:      total_pages,
    next_page:      if (i + 1) <= total_pages then "/blog/categories/#{category}/page/#{i+1}" else false end,
    prev_page:      prev_page,
    total_articles: total_articles
  }
end

ready do
  per_page = 10

  # Loop through all articles and group them by category and then loop through each group
  blog.articles.group_by {|a| a.data.category }.each do |category, articles|
    total_pages    = articles.size.fdiv(per_page).ceil # Calculate the numer of pages
    total_articles = articles.size
    page_articles  = articles.slice(0, per_page) # Get the articles for the page

    # Create a proxy for the main/first category page
    proxy "/blog/categories/#{category}.html", "/category.html", locals: get_locals(category, total_pages, 1, page_articles, total_articles)

    # Create pages for each of the pagination
    (1..total_pages).each do |i|
      page_articles = articles.slice((i - 1) * per_page, per_page)
      proxy "/blog/categories/#{category}/page/#{i}", "/category.html", locals: get_locals(category, total_pages, i, page_articles, total_articles)
    end

  end
end