"DEPRECATION WARNING: class_inheritable_attribute is deprecated...." when executing rake db:create

When I follow the Spree Guides, I got an error message ,

yulong@ubuntu:~/mystore$ rake db:create
rake db:create
    DEPRECATION WARNING: class_inheritable_attribute is deprecated, please use class_attribute method instead. Notice their behavior are slightly different, so refer to class_attribute documentation first. (called from <top (required)> at /home/yulong/mystore/config/application.rb:7)
    DEPRECATION WARNING: class_inheritable_attribute is deprecated, please use class_attribute method instead. Notice their behavior are slightly different, so refer to class_attribute documentation first. (called from <top (required)> at /home/yulong/mystore/config/application.rb:7)
    DEPRECATION WARNING: class_inheritable_attribute is deprecated, please use class_attribute method instead. Notice their behavior are slightly different, so refer to class_attribute documentation first. (called from <top (required)> at /home/yulong/mystore/config/application.rb:7)
    DEPRECATION WARNING: class_inheritable_attribute is deprecated, please use class_attribute method instead. Notice their behavior are slightly different, so refer to class_attribute documentation first. (called from <top (required)> 开发者_开发百科at /home/yulong/mystore/config/application.rb:7)
    rake aborted!
    Fixtures is not a class
yulong@ubuntu:~/mystore$ rails g spree:site
    DEPRECATION WARNING: class_inheritable_attribute is deprecated, please use class_attribute method instead. Notice their behavior are slightly different, so refer to class_attribute documentation first. (called from <top (required)> at /home/yulong/mystore/config/application.rb:7)
    DEPRECATION WARNING: class_inheritable_attribute is deprecated, please use class_attribute method instead. Notice their behavior are slightly different, so refer to class_attribute documentation first. (called from <top (required)> at /home/yulong/mystore/config/application.rb:7)
    DEPRECATION WARNING: class_inheritable_attribute is deprecated, please use class_attribute method instead. Notice their behavior are slightly different, so refer to class_attribute documentation first. (called from <top (required)> at /home/yulong/mystore/config/application.rb:7)
    DEPRECATION WARNING: class_inheritable_attribute is deprecated, please use class_attribute method instead. Notice their behavior are slightly different, so refer to class_attribute documentation first. (called from <top (required)> at /home/yulong/mystore/config/application.rb:7)
    [DEPRECATION WARNING] Nested I18n namespace lookup under "activerecord.attributes.checkout" is no longer supported
   create  lib/spree_site.rb
   remove  public/index.html
   append  public/robots.txt
   append  db/seeds.rb

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Please go through following link, which will help you to fix this issue in rails 3.1

http://martinciu.com/2011/07/difference-between-class_inheritable_attribute-and-class_attribute.html