Page xv invites us to run the example app with rails s. I get this error:
Showing <APP_DIR>/turbo/01/app/views/concerts/_schedule_concert.html.erb where line #37 raised:
undefined method `favorite' for nil:NilClass
It seems current_user is undefined.
There is definitely some code in there that needs a logged in user and should be cleaned up for the next beta. This should be fixed if you log in (going directly to http://localhost:3000/users/sign_in if you need to, the seeded users are in the seeds.rb file, I think you can use areader@example.com with awesome.