WARNING: Global access to Rake DSL methods is deprecated. Please include

在运行rake脚本的时候，出现这样的警告：
WARNING: Global access to Rake DSL methods is deprecated.  Please include
    ...  Rake::DSL into classes and modules which use the Rake DSL methods.

WARNING: DSL method DemoApp::Application#task called at /usr/local/lib/ruby/gems/1.8/gems/railties-3.0.4/lib/rails/application.rb:214:in `initialize_tasks'

在Rakefile中的DemoApp::Application.load_tasks之前前再加上include Rake::DSL即可解决。