最近在学习用 Padrino 0.13 ruby 2.2 ActiveRecord 4.2

config/root.rb

#initialize redis and ActiveRecord Cache
CACHE = ActiveSupport::Cache::RedisStore.new :host => "127.0.0.1", :driver => :hiredis, :expires_in => 1.week
CACHE.logger = logger

SecondLevelCache.configure do |config|
  config.cache_store = CACHE
  config.logger = logger
  config.cache_key_prefix = ''
end

config/database.rb

ActiveRecord::Base.raise_in_transactional_callbacks = false

在测试环境中运行

thin start

都会出现以下警告信息

You can opt into the new behavior and remove this warning by setting:

  config.active_record.raise_in_transactional_callbacks = true

请问如何才能去掉这个警告信息~