RoR Guía de introducción: Rake db: migrar el método no definido 'referencia'

Question

Estoy siguiendo el RoR Getting Started tutorial. Después de haber creado publicaciones, ahora estoy agregando el segundo modelo para crear comentarios. Sin embargo, cuando intento rastrillo db:migrate me sale esto:

** Invoke db:migrate (first_time) 
** Invoke environment (first_time) 
** Execute environment 
** Invoke db:load_config (first_time) 
** Invoke rails_env (first_time) 
** Execute rails_env 
** Execute db:load_config 
** Execute db:migrate 
== CreateComments: migrating ================================================= 
-- create_table(:comments) 
rake aborted! 
An error has occurred, this and all later migrations canceled: 

undefined method `reference' for #<ActiveRecord::ConnectionAdapters::TableDefinition:0x1084a24d8> 
/Users/Fryed/rails/blog/db/migrate/20120710225337_create_comments.rb:6:in `change' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/connection_adapters/abstract/schema_statements.rb:160:in `create_table' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/migration.rb:466:in `send' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/migration.rb:466:in `method_missing' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/migration.rb:438:in `say_with_time' 
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/benchmark.rb:293:in `measure' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/migration.rb:438:in `say_with_time' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/migration.rb:458:in `method_missing' 
/Users/Fryed/rails/blog/db/migrate/20120710225337_create_comments.rb:3:in `change' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/migration.rb:407:in `migrate' 
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/benchmark.rb:293:in `measure' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/migration.rb:407:in `migrate' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/connection_adapters/abstract/connection_pool.rb:123:in `with_connection' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/migration.rb:389:in `migrate' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/migration.rb:528:in `__send__' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/migration.rb:528:in `migrate' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/migration.rb:720:in `migrate' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/migration.rb:775:in `call' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/migration.rb:775:in `ddl_transaction' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/connection_adapters/abstract/database_statements.rb:192:in `transaction' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/transactions.rb:208:in `transaction' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/migration.rb:775:in `ddl_transaction' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/migration.rb:719:in `migrate' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/migration.rb:700:in `each' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/migration.rb:700:in `migrate' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/migration.rb:570:in `up' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/migration.rb:551:in `migrate' 
/Library/Ruby/Gems/1.8/gems/activerecord-3.2.6/lib/active_record/railties/databases.rake:153 
/Library/Ruby/Gems/1.8/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `call' 
/Library/Ruby/Gems/1.8/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `execute' 
/Library/Ruby/Gems/1.8/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `each' 
/Library/Ruby/Gems/1.8/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `execute' 
/Library/Ruby/Gems/1.8/gems/rake-0.9.2.2/lib/rake/task.rb:158:in `invoke_with_call_chain' 
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/1.8/monitor.rb:242:in `synchronize' 
/Library/Ruby/Gems/1.8/gems/rake-0.9.2.2/lib/rake/task.rb:151:in `invoke_with_call_chain' 
/Library/Ruby/Gems/1.8/gems/rake-0.9.2.2/lib/rake/task.rb:144:in `invoke' 
/Library/Ruby/Gems/1.8/gems/rake-0.9.2.2/lib/rake/application.rb:116:in `invoke_task' 
/Library/Ruby/Gems/1.8/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `top_level' 
/Library/Ruby/Gems/1.8/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `each' 
/Library/Ruby/Gems/1.8/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `top_level' 
/Library/Ruby/Gems/1.8/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling' 
/Library/Ruby/Gems/1.8/gems/rake-0.9.2.2/lib/rake/application.rb:88:in `top_level' 
/Library/Ruby/Gems/1.8/gems/rake-0.9.2.2/lib/rake/application.rb:66:in `run' 
/Library/Ruby/Gems/1.8/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling' 
/Library/Ruby/Gems/1.8/gems/rake-0.9.2.2/lib/rake/application.rb:63:in `run' 
/Library/Ruby/Gems/1.8/gems/rake-0.9.2.2/bin/rake:33 
/usr/bin/rake:23:in `load' 
/usr/bin/rake:23 
Tasks: TOP => db:migrate 

estoy corriendo:

Rake 0.9.2.2. de Ruby 1.8.7 Rails 3.2.6

Answer 1

migraciones con referencias usan el helper references, es probable que sólo se olvidó de poner el s al final.

Encuentra la migración infractor db/migrate/20120710225337_create_comments.rb y el cambio de reference a references