RoR Guida introduttiva: Rake db: migrazione del metodo non definito 'reference'

Question

Sto seguendo lo RoR Getting Started tutorial. Dopo aver creato post, ora sto aggiungendo il secondo modello per creare commenti. Tuttavia, quando provo rastrello db:migrate ottengo questo:

** 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 

sto correndo:

Rake 0.9.2.2. di Ruby 1.8.7 Rails 3.2.6

Answer 1

migrazioni con riferimenti utilizzare il references aiutante, è probabilmente solo dimenticato di mettere il s alla fine.

Trova la migrazione incriminato db/migrate/20120710225337_create_comments.rb e cambiamento da reference a references