, , , prod. cookie . .
config.action_controller.session = {:domain => '.localhost:3000'}
,
config.action_controller.session = {:domain => '.com'}
, localhost.localdomain dummylocal.com, - , .
config.action_controller.session = {:domain => 'localhost.localdomain'}
config.action_controller.session = {:domain => 'dummylocal.com'}