/lib/facebooker/rails/helpers.rb

helpers.rb

module Facebooker

  def self.api_key
    unless @_api_key
      config = (YAML.load(ERB.new(File.read(File.join(::Rails.root,"config","facebooker.yml"))).result)[::Rails.env])
      @_api_key = config["api_key"]
    end
    @_api_key
  end

...
      # Return the URL for the about page of the application
      def fb_about_url
        "http://www.facebook.com/apps/application.php?api_key=#{Facebooker.api_key}"
      end
...
end