Some libraries for Rails 3 still depend to rake 0.9

In this week, both Rails 3.2.9 and Rake 10.x have been released. Rails itself does not depend to rake version. But, some libraries of Rails 3 are depending to rake 0.9.x. so we should fix Gemfile like below:

gem 'rails', '3.2.9'
gem 'rake', '~> 0.9'