Automatically cache pages in Rails, put this in /lib/tasks/cache.rake

cache.rake

# See rails source:
# https://github.com/rails/rails/blob/master/actionpack/lib/action_controller/caching/pages.rb
#
# Turn on caching in development, by changing this line to true in config/environments/development.rb:
#
#     config.action_controller.perform_caching = true
#
# Then run:
#
#     bundle exec rake pages:cache
#
# All cached pages will be in /public/path_name/xxxx.html

namespace :pages do
  desc "Cache ALL the pages!"
  task :cache => :environment do

    # First, let's instantiate a new session so we can `get` our paths,
    # just like if we were writing an integration test
    app = ActionDispatch::Integration::Session.new(Rails.application)

    # Now, we'll loop through each path we want to cache
    %w( /index /about /contact /products /products/cool_thing /products/other_cool_thing ).each do |path|

      # Get the path
      app.get path

      # Let's figure out the file path/name to which we're saving the file
      file_path = "/cache/#{path.gsub('/', '_')[1,path.length]}"

      # And now let's cache the response body HTML, using the ActionController's
      ApplicationController.cache_page(app.response.body, file_path)
    end
  end
end

This was a huge help! THANK YOU!

If you're doing this as part of a build/deploy you may want to include:

    app.https!
    app.host! "www.exmaple.com" # replace with your domain!

Otherwise you may get root_url and other uses of host pointing at http://www.example.com instead of your domain!