是什么导致这些设计错误？

Question

我正在尝试像这样设置Devise：

$ rails generate devise:install
...
$ rails generate devise User
...
$ rake db:migrate --stack

rake db:migrate --stack 行导致此错误：

WARNING: Global access to Rake DSL methods is deprecated.  Please include
    ...  Rake::DSL into classes and modules which use the Rake DSL methods.
WARNING: DSL method Elephant::Application#task called at /Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application.rb:214:in `initialize_tasks'
** Invoke db:migrate (first_time)
** Invoke environment (first_time)
** Execute environment
rake aborted!
undefined method `devise' for User(Table doesn't exist):Class
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activerecord-3.0.1/lib/active_record/base.rb:1016:in `method_missing'
/Users/ben/rails_projects/elephant/app/models/user.rb:4:in `<class:User>'
/Users/ben/rails_projects/elephant/app/models/user.rb:1:in `<top (required)>'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:454:in `load'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:454:in `block in load_file'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:591:in `new_constants_in'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:453:in `load_file'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:340:in `require_or_load'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:491:in `load_missing_constant'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:183:in `block in const_missing'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:181:in `each'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:181:in `const_missing'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/inflector/methods.rb:124:in `block in constantize'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/inflector/methods.rb:123:in `each'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/inflector/methods.rb:123:in `constantize'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:523:in `block in <class:Reference>'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:533:in `yield'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:533:in `default'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:533:in `get'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/devise-1.1.5/lib/devise/mapping.rb:69:in `to'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/devise-1.1.5/lib/devise/mapping.rb:64:in `modules'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/devise-1.1.5/lib/devise/mapping.rb:73:in `strategies'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/devise-1.1.5/lib/devise.rb:281:in `block in configure_warden!'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/devise-1.1.5/lib/devise.rb:280:in `each_value'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/devise-1.1.5/lib/devise.rb:280:in `configure_warden!'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/devise-1.1.5/lib/devise/rails/routes.rb:7:in `finalize_with_devise!'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application.rb:128:in `block in reload_routes!'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/lazy_load_hooks.rb:36:in `instance_eval'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/lazy_load_hooks.rb:36:in `execute_hook'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/lazy_load_hooks.rb:26:in `on_load'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application.rb:128:in `reload_routes!'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application.rb:120:in `block in routes_reloader'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/file_update_checker.rb:32:in `call'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/file_update_checker.rb:32:in `execute_if_updated'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/actionpack-3.0.1/lib/action_dispatch/railtie.rb:14:in `block (2 levels) in <class:Railtie>'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/callbacks.rb:419:in `_run_prepare_callbacks'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/actionpack-3.0.1/lib/action_dispatch/middleware/callbacks.rb:40:in `initialize'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/actionpack-3.0.1/lib/action_dispatch/middleware/stack.rb:33:in `new'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/actionpack-3.0.1/lib/action_dispatch/middleware/stack.rb:33:in `build'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/actionpack-3.0.1/lib/action_dispatch/middleware/stack.rb:79:in `block in build'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/actionpack-3.0.1/lib/action_dispatch/middleware/stack.rb:79:in `each'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/actionpack-3.0.1/lib/action_dispatch/middleware/stack.rb:79:in `inject'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/actionpack-3.0.1/lib/action_dispatch/middleware/stack.rb:79:in `build'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application.rb:162:in `app'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application/finisher.rb:35:in `block in <module:Finisher>'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/initializable.rb:25:in `instance_exec'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/initializable.rb:25:in `run'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/initializable.rb:50:in `block in run_initializers'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/initializable.rb:49:in `each'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/initializable.rb:49:in `run_initializers'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application.rb:134:in `initialize!'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application.rb:77:in `method_missing'
/Users/ben/rails_projects/elephant/config/environment.rb:5:in `<top (required)>'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:239:in `require'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:239:in `block in require'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:225:in `block in load_dependency'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:591:in `new_constants_in'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:225:in `load_dependency'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:239:in `require'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application.rb:103:in `require_environment!'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application.rb:216:in `block in initialize_tasks'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:205:in `call'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:205:in `block in execute'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:200:in `each'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:200:in `execute'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:158:in `block in invoke_with_call_chain'
/Users/ben/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:151:in `invoke_with_call_chain'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:176:in `block in invoke_prerequisites'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:174:in `each'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:174:in `invoke_prerequisites'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:157:in `block in invoke_with_call_chain'
/Users/ben/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:151:in `invoke_with_call_chain'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:144:in `invoke'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/application.rb:112:in `invoke_task'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/application.rb:90:in `block (2 levels) in top_level'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/application.rb:90:in `each'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/application.rb:90:in `block in top_level'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/application.rb:129:in `standard_exception_handling'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/application.rb:84:in `top_level'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/application.rb:62:in `block in run'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/application.rb:129:in `standard_exception_handling'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/application.rb:59:in `run'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/bin/rake:32:in `<top (required)>'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/bin/rake:19:in `load'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/bin/rake:19:in `<main>'
Tasks: TOP => db:migrate => environment

user.rb 如下所示：

class User < ActiveRecord::Base
  # Include default devise modules. Others available are:
  # :token_authenticatable, :confirmable, :lockable and :timeoutable
  devise :database_authenticatable, :registerable,
         :recoverable, :rememberable, :trackable, :validatable

  # Setup accessible (or protected) attributes for your model
  attr_accessible :email, :password, :password_confirmation, :remember_me
end

如果我注释掉 devise :database_authenticatable... 行，并运行 rake db:migrate --stack，我明白了此错误：

WARNING: Global access to Rake DSL methods is deprecated.  Please include
    ...  Rake::DSL into classes and modules which use the Rake DSL methods.
WARNING: DSL method Elephant::Application#task called at /Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application.rb:214:in `initialize_tasks'
** Invoke db:migrate (first_time)
** Invoke environment (first_time)
** Execute environment
rake aborted!
User does not respond to 'devise' method. This usually means you haven't loaded your ORM file or it's being loaded too late. To fix it, be sure to require 'devise/orm/YOUR_ORM' inside 'config/initializers/devise.rb' or before your application definition in 'config/application.rb'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/devise-1.1.5/lib/devise/rails/routes.rb:245:in `raise_no_devise_method_error!'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/devise-1.1.5/lib/devise/rails/routes.rb:140:in `block in devise_for'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/devise-1.1.5/lib/devise/rails/routes.rb:136:in `each'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/devise-1.1.5/lib/devise/rails/routes.rb:136:in `devise_for'
/Users/ben/rails_projects/elephant/config/routes.rb:4:in `block in <top (required)>'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/actionpack-3.0.1/lib/action_dispatch/routing/route_set.rb:233:in `instance_exec'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/actionpack-3.0.1/lib/action_dispatch/routing/route_set.rb:233:in `draw'
/Users/ben/rails_projects/elephant/config/routes.rb:1:in `<top (required)>'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:235:in `load'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:235:in `block in load'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:225:in `block in load_dependency'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:591:in `new_constants_in'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:225:in `load_dependency'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:235:in `load'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application.rb:127:in `block in reload_routes!'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application.rb:127:in `each'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application.rb:127:in `reload_routes!'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application.rb:120:in `block in routes_reloader'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/file_update_checker.rb:32:in `call'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/file_update_checker.rb:32:in `execute_if_updated'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/actionpack-3.0.1/lib/action_dispatch/railtie.rb:14:in `block (2 levels) in <class:Railtie>'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/callbacks.rb:419:in `_run_prepare_callbacks'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/actionpack-3.0.1/lib/action_dispatch/middleware/callbacks.rb:40:in `initialize'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/actionpack-3.0.1/lib/action_dispatch/middleware/stack.rb:33:in `new'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/actionpack-3.0.1/lib/action_dispatch/middleware/stack.rb:33:in `build'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/actionpack-3.0.1/lib/action_dispatch/middleware/stack.rb:79:in `block in build'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/actionpack-3.0.1/lib/action_dispatch/middleware/stack.rb:79:in `each'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/actionpack-3.0.1/lib/action_dispatch/middleware/stack.rb:79:in `inject'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/actionpack-3.0.1/lib/action_dispatch/middleware/stack.rb:79:in `build'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application.rb:162:in `app'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application/finisher.rb:35:in `block in <module:Finisher>'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/initializable.rb:25:in `instance_exec'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/initializable.rb:25:in `run'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/initializable.rb:50:in `block in run_initializers'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/initializable.rb:49:in `each'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/initializable.rb:49:in `run_initializers'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application.rb:134:in `initialize!'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application.rb:77:in `method_missing'
/Users/ben/rails_projects/elephant/config/environment.rb:5:in `<top (required)>'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:239:in `require'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:239:in `block in require'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:225:in `block in load_dependency'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:591:in `new_constants_in'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:225:in `load_dependency'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/activesupport-3.0.1/lib/active_support/dependencies.rb:239:in `require'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application.rb:103:in `require_environment!'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/railties-3.0.1/lib/rails/application.rb:216:in `block in initialize_tasks'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:205:in `call'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:205:in `block in execute'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:200:in `each'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:200:in `execute'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:158:in `block in invoke_with_call_chain'
/Users/ben/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:151:in `invoke_with_call_chain'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:176:in `block in invoke_prerequisites'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:174:in `each'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:174:in `invoke_prerequisites'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:157:in `block in invoke_with_call_chain'
/Users/ben/.rvm/rubies/ruby-1.9.2-p0/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:151:in `invoke_with_call_chain'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/task.rb:144:in `invoke'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/application.rb:112:in `invoke_task'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/application.rb:90:in `block (2 levels) in top_level'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/application.rb:90:in `each'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/application.rb:90:in `block in top_level'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/application.rb:129:in `standard_exception_handling'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/application.rb:84:in `top_level'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/application.rb:62:in `block in run'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/application.rb:129:in `standard_exception_handling'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/lib/rake/application.rb:59:in `run'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/gems/rake-0.9.2/bin/rake:32:in `<top (required)>'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/bin/rake:19:in `load'
/Users/ben/.rvm/gems/ruby-1.9.2-p0/bin/rake:19:in `<main>'
Tasks: TOP => db:migrate => environment

是什么导致了这些错误？

我正在运行 Rails 3.0.1 和 Ruby 1.9.2

Answer 1

你使用的是 ruby​​ 1.8.7 & 吗？耙子0.9~？

试试这个：

module ::YOUR_APP_NAME
  class Application
      include Rake::DSL
  end
end