app/controllers/sitemap_controller.rb
require 'open-uri'
class SitemapController < ApplicationController
def index
data = open("https://s3.amazonaws.com/#{ENV['S3_BUCKET_NAME']}/sitemaps/sitemap.xml.gz")
send_data(data.read, filename: 'sitemap.xml.gz', type: 'application/gzip', stream: true)
end
end