Ruby on Rails

I'm reading the rails tutorial book and in chapter 6 page 199 I have
to make a rake db:migrate, but I get this error:

rake aborted! undefined method `prerequisites' for nil:NilClass

(See full trace by running task with --trace)

When I try with rake db:migrate --trace I get the following errors:

rake aborted!
undefined method `prerequisites' for nil:NilClass
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/rspec-rails-2.0.1/lib/
rspec/rails/tasks/rspec.rake:3:in `<top (required)>'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/rspec-rails-2.0.1/lib/
rspec-rails.rb:10:in `load'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/rspec-rails-2.0.1/lib/
rspec-rails.rb:10:in `block in <class:Railtie>'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.1/lib/
rails/railtie.rb:183:in `call'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.1/lib/
rails/railtie.rb:183:in `block in load_tasks'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.1/lib/
rails/railtie.rb:183:in `each'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.1/lib/
rails/railtie.rb:183:in `load_tasks'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.1/lib/
rails/engine.rb:396:in `block in load_tasks'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.1/lib/
rails/application/railties.rb:8:in `each'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.1/lib/
rails/application/railties.rb:8:in `all'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.1/lib/
rails/engine.rb:396:in `load_tasks'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.1/lib/
rails/application.rb:103:in `load_tasks'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/railties-3.1.1/lib/
rails/railtie/configurable.rb:30:in `method_missing'
/Users/jeanosorio/ror/sample_app/Rakefile:7:in `<top (required)>'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2/lib/rake/
rake_module.rb:25:in `load'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2/lib/rake/
rake_module.rb:25:in `load_rakefile'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2/lib/rake/
application.rb:495:in `raw_load_rakefile'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2/lib/rake/
application.rb:78:in `block in load_rakefile'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2/lib/rake/
application.rb:129:in `standard_exception_handling'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2/lib/rake/
application.rb:77:in `load_rakefile'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2/lib/rake/
application.rb:61:in `block in run'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2/lib/rake/
application.rb:129:in `standard_exception_handling'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2/lib/rake/
application.rb:59:in `run'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/gems/rake-0.9.2/bin/rake:
32:in `<top (required)>'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/bin/rake:19:in `load'
/Users/jeanosorio/.rvm/gems/ruby-1.9.2-p290/bin/rake:19:in `<main>'

I tried update my gems, but I still get the last error. Can anybody
help me to solve this issues please.

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