rails--rails/activemodel/lib/active_model/railtie.rb

require "active_model"
require "rails"

module ActiveModel
  class Railtie < Rails::Railtie # :nodoc:
    config.eager_load_namespaces << ActiveModel

    initializer "active_model.secure_password" do
      ActiveModel::SecurePassword.min_cost = Rails.env.test?
    end
  end
end