class AppRegistry
  extend RequestRegistry.new(:user, :account)
end

class ApplicationController < ActionController::Base
  before_action :provide_registry_information

  private

  def provide_registry_information
    AppRegistry.user = current_user
    AppRegistry.account = 'my awesome account'
  end
end

class Post < ActionController::Base
  belongs_to :author
  before_save :set_author

  private

  def set_author
    self.author = AppRegistry.user.presence
  end
end