ruby on rails - "NameError - uninitialized constant" when running function from singleton model -

i'm getting "nameerror - uninitialized constant store::directededge" when call below statement controller.

store.instance.add_purchase(1, 2) 

below singleton 'store' model:

require 'singleton'  class store    include singleton    def initialize     @database = directededge::database.new(env['directed_edge_username'], env['directed_edge_password'])   end    def add_purchase(user_id, product_id)     item = directededge::item.new(@database, "user#{user_id}")     item.link_to("product#{product_id}", "purchase")     item.save   end    ...  end 

anyone have idea problem is?

try require directededge require 'directed_edge'. here link documentation directed edge example.