Something’s a little off. Your message indicates that version 2.0.0 of jquery-rails is missing. The 2nd edition of the Rails Tutorial uses version 2.0.2, not 2.0.0. If you have 2.0.2 in your gemfile, It is possible that one of the other gems is requiring 2.0.0 as a dependency.
If that’s the case, I would force the install of version 2.0.0 as follows:
gem install jquery-rails --version ‘2.0.0’
It is very important that you use the version of the gems specified in the book. In particular, if you do not use the same version of rspec and capybara as the book does, you will have real problems. FYI, the full source code of the application you will be building in the tutorial (which includes the gemfile) is available at: