#### core/lib/spree_core/railtie.rb #####

    initializer "spree.environment" do |app|
      app.config.spree = Spree::Environment.new
    end

    initializer "spree.register.payments" do |app|
      app.config.spree.payment_methods = [
          Gateway::Bogus,
          Gateway::AuthorizeNet,
          Gateway::AuthorizeNetCim,
          Gateway::Eway,
          Gateway::Linkpoint,
          Gateway::PayPal,
          Gateway::SagePay,
          Gateway::Beanstream,
          Gateway::Braintree,
          PaymentMethod::Check ]
     end

#### core/lib/spree/environment.rb #####

module Spree
  class Environment
    attr_accessor :calculators, :payment_methods
  end
end

#### core/app/models/payment_methods #####

  def self.providers
    Rails.application.config.spree.payment_methods
  end