Ruby newbie: undefined method `with_indifferent_access'

I am a new Ruby programmer, and a co-worker of mine to help me get started wrote the following code which ran fine in his environment. However, when I try to run it in my own environment, I ge the follow error: undefined method 'with_indifferent_access' for #<Hash:0x1012392c0> (NoMethodError)

The method in question appears twice in the code:

require 'rubygems'

gem 'activerecord'
gem 'activesupport'
gem 'sailthru-client'

require 'active_support'
require 'active_record'
require 'sailthru'

# Setup our Sailthru object using our production Sailthru account information
sailthru = Sailthru::SailthruClient.new()

# Read database information from the database.yml file
CONFIG = YAML.load_file(File.join(File.dirname(__FILE__), 'database.yml')).with_indifferent_access

# Create a simple way for us to iterate through all publications
class Publication < ActiveRecord::Base
  establish_connection CONFIG[:production]
  set_table_name 'publications'
end

# Create a simple way for us to store data locally
class CurrentReport < ActiveRecord::Base
  establish_connection CONFIG[:development]
  set_table_name 'current_reports'
end

class MonthlyReport < ActiveRecord::Base
  establish_connection CONFIG[:development]
  set_table_name 'monthly_reports'
end

types = %w[Daily Weekly]

Publication.find_each(:select => :id) do |publication|
  begin
    types.each do |newsletter_type|
      # Get the stats for each mailing list
      response = sailthru.stats_list("#{newsletter_type} Newsletter - #{publication.id}").with_indifferent_access

      if response[:error]
        puts "Sailthru Error #{response[:error]}: #{response[:errormsg]}"
      else
        # Try to fin开发者_如何学运维d an existing record for this newsletter
        daily = CurrentReport.find_or_initialize_by_list(response[:list])
        # and update it with the information from the response (minus the monthly signup info)
        puts "Updating #{newsletter_type} Newsletter - #{publication.id} ..."
        daily.update_attributes(response.reject { |k,v| k =~ /signup/ })

        # Iterate through the monthly signup info
        response['signup_month'].each do |k, v|
          # And try to save it
          monthly = MonthlyReport.find_or_initialize_by_list_and_month(response[:list], k)
          # Only save new months, because the old months never change
          if monthly.new_record?
            monthly.update_attributes(v)
            puts "\tAdding #{v[:month]} to #{response[:list]} ..."
          end
        end
      end
    end
#  rescue NoMethodError => e
#    puts "Got a NoMethodError for some reason.  Here's the publication: #{publication.inspect}\n\nHere's the types array: #{types}"
  end
end

I have tried different versions of ruby, such as ruby-1.8.7, to no avail. I am at a loss on how to solve this problem. I know this method exists somewhere because I have seen it work. I am open to any suggestions on what to try next.

Try using:

require 'active_support/core_ext/hash'

Thats what actually adds the with_indifferent_access method to the normal Hash class.

By the way, HashWithIndifferentAccess is really powerful as long as you use it with caution.

For example:

h = HashWithIndifferentAccess.new()
some_array.each do |a|
  h["#{a}"] = "anything you want"
end

I use it all the time when working with slices of data in metrics.