how to overload device settings?

application_controller.rb

  before_filter :config_old_domain

  def config_old_domain
    return if request.domain == Settings.domain

    Devise.setup do |config|
      config.omniauth(
        :facebook,
        Settings.omniauth.old_facebook.app_id,
        Settings.omniauth.old_facebook.app_secret,
        {:client_options => {:ssl =>
          {:ca_path => '/etc/pki/tls/certs/',
           :ca_file => '/etc/pki/tls/certs/ca-bundle.crt'}
        }}
      )
    end
  end