I am sorry for asking what may be a remedial question, but in learning rails i was trying to follow along note for note in this tutorial:
http://guides.rubyonrails.
That line in section 5.7 is just showing you the output of rake routes, it's not meant to be in your config/routes.rb file.
The line resources :posts in routes.rb generates the show posts route for you, test it by removing the line: post GET /posts/:id(.:format) posts#show and then running rake routes on the command line.