非常的有效，效果扛扛的
config.action_controller.perform_caching = true#实际中改一下为true
测试时改为false
4.2 Being Specific
If you need to run a specific migration up or down the db:migrate:up and db:migrate:downtasks will do that. Just specify the appropriate version and the corresponding migration will have itsup or down method invoked, for example
rake db:migrate:up VERSION=20080906120000 |
will run the up method from the 20080906120000 migration. These tasks check whether the migration has already run, so for example db:migrate:up VERSION=20080906120000 will do nothing if Active Record believes that 20080906120000 has already been run.