Get an AppConfig file in your app

app_config.rb

# This goes to Rails.root/lib
# Requires the hashie gem

::AppConfig = begin
  config_file = File.expand_path('../../config/config.yml', __FILE__)
  config = Hashie::Mash.new YAML.load_file( config_file )[ Rails.env ]

  local_config_file = File.expand_path('../../config/config.local.yml', __FILE__)
  if File.exists? local_config_file
    config.merge! YAML.load_file( local_config_file )[ Rails.env ] || {}
  end

  config
end

application.rb

require File.expand_path('../boot', __FILE__)

require 'rails/all'

# If you have a Gemfile, require the gems listed there, including any gems
# you've limited to :test, :development, or :production.
Bundler.require(:default, Rails.env) if defined?(Bundler)
require File.expand_path('../../lib/app_config', __FILE__) # <-- Here we load the config 

module YourApp
  class Application < Rails::Application
    # Your app config
  end
end