Ruby on rails Spree：未定义的方法`首选项定义'；零级：零级

我正在尝试在本地计算机上启动RoR应用程序。在运行rake

db:bootstrap

时，一切正常，直到：

Create the admin user (press enter for defaults).
Email [spree@example.com]: 
Password [spree123]: 
rake aborted!
undefined method `preference_definitions' for nil:NilClass
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/bundler/gems/spree-22cd84cc71d9/core/app/models/preference.rb:31:in `definition'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/bundler/gems/spree-22cd84cc71d9/core/app/models/preference.rb:37:in `value'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activemodel-3.1.10/lib/active_model/dirty.rb:143:in `attribute_change'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activemodel-3.1.10/lib/active_model/dirty.rb:117:in `block in changes'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activemodel-3.1.10/lib/active_model/dirty.rb:117:in `map'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activemodel-3.1.10/lib/active_model/dirty.rb:117:in `changes'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/attribute_methods/dirty.rb:34:in `block in save!'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/attribute_methods/dirty.rb:33:in `tap'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/attribute_methods/dirty.rb:33:in `save!'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/transactions.rb:246:in `block in save!'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/transactions.rb:295:in `block in with_transaction_returning_status'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/connection_adapters/abstract/database_statements.rb:194:in `transaction'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/transactions.rb:208:in `transaction'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/transactions.rb:293:in `with_transaction_returning_status'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/transactions.rb:246:in `save!'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/bundler/gems/spree-22cd84cc71d9/core/lib/spree_core/preferences/model_hooks.rb:287:in `block (2 levels) in update_preferences'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/bundler/gems/spree-22cd84cc71d9/core/lib/spree_core/preferences/model_hooks.rb:275:in `each'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/bundler/gems/spree-22cd84cc71d9/core/lib/spree_core/preferences/model_hooks.rb:275:in `block in update_preferences'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/bundler/gems/spree-22cd84cc71d9/core/lib/spree_core/preferences/model_hooks.rb:274:in `each'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/bundler/gems/spree-22cd84cc71d9/core/lib/spree_core/preferences/model_hooks.rb:274:in `update_preferences'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activesupport-3.1.10/lib/active_support/callbacks.rb:401:in `_run_save_callbacks'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activesupport-3.1.10/lib/active_support/callbacks.rb:81:in `run_callbacks'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/callbacks.rb:264:in `create_or_update'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/persistence.rb:37:in `save'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/validations.rb:50:in `save'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/attribute_methods/dirty.rb:22:in `save'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/transactions.rb:241:in `block (2 levels) in save'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/transactions.rb:295:in `block in with_transaction_returning_status'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/connection_adapters/abstract/database_statements.rb:194:in `transaction'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/transactions.rb:208:in `transaction'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/transactions.rb:293:in `with_transaction_returning_status'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/transactions.rb:241:in `block in save'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/transactions.rb:252:in `rollback_active_record_state!'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/transactions.rb:240:in `save'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/bundler/gems/spree-22cd84cc71d9/core/lib/spree/preference_access.rb:20:in `set'
/home/nishant/voylla_website/db/seeds.rb:13:in `<top (required)>'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activesupport-3.1.10/lib/active_support/dependencies.rb:234:in `load'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activesupport-3.1.10/lib/active_support/dependencies.rb:234:in `block in load'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activesupport-3.1.10/lib/active_support/dependencies.rb:223:in `block in load_dependency'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activesupport-3.1.10/lib/active_support/dependencies.rb:640:in `new_constants_in'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activesupport-3.1.10/lib/active_support/dependencies.rb:223:in `load_dependency'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activesupport-3.1.10/lib/active_support/dependencies.rb:234:in `load'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/railties-3.1.10/lib/rails/engine.rb:488:in `load_seed'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/railties/databases.rake:301:in `block (2 levels) in <top (required)>'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/bundler/gems/spree-22cd84cc71d9/core/lib/tasks/core.rake:93:in `block (2 levels) in <top (required)>'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/bin/ruby_noexec_wrapper:14:in `eval'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/bin/ruby_noexec_wrapper:14:in `<main>'
Tasks: TOP => db:seed
(See full trace by running task with --trace)

创建管理员用户（按enter键获取默认值）。
电子邮件[spree@example.com]: 
密码[spree123]：
雷克流产了！
nil:NilClass的未定义方法“首选项定义”
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/bundler/gems/spree-22cd84cc71d9/core/app/models/preference.rb:31:在“定义”中
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/bundler/gems/spree-22cd84cc71d9/core/app/models/preference.rb:37:in'value'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activemodel-3.1.10/lib/active\u model/dirty.rb:143:在'attribute\u change'中
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activemodel-3.1.10/lib/active\u model/dirty.rb:117:在“更改中的块”中
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activemodel-3.1.10/lib/active\u model/dirty.rb:117:in'map'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activemodel-3.1.10/lib/active\u model/dirty.rb:117:in'changes'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active\u record/attribute\u methods/dirty.rb:34:在“保存中的块”中
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active\u record/attribute\u methods/dirty.rb:33:in'tap'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active\u record/attribute\u methods/dirty.rb:33:in'save！'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/transactions.rb:246:in`block in save！'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active\u record/transactions.rb:295:in‘阻塞输入，事务返回状态’
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active\u record/connection\u adapters/abstract/database\u语句。rb:194:in'transaction'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/transactions.rb:208:in'transaction'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active\u record/transactions.rb:293:in`with\u transaction\u returning\u status'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/transactions.rb:246:in'save！'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/bundler/gems/spree-22cd84cc71d9/core/lib/spree\u core/preferences/model\u hooks.rb:287:在“更新\u首选项中的块（2级）”中
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/bundler/gems/spree-22cd84cc71d9/core/lib/spree_core/preferences/model_hooks.rb:275:in'each'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/bundler/gems/spree-22cd84cc71d9/core/lib/spree\u core/preferences/model\u hooks.rb:275:in'block in update\u preferences'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/bundler/gems/spree-22cd84cc71d9/core/lib/spree\u core/preferences/model\u hooks.rb:274:in'each'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/bundler/gems/spree-22cd84cc71d9/core/lib/spree\u core/preferences/model\u hooks.rb:274:in'update\u preferences'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activesupport-3.1.10/lib/active\u-support/callbacks.rb:401:在“运行\u保存\u回调”中
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activesupport-3.1.10/lib/active\u support/callbacks.rb:81:in'run\u callbacks'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active\u record/callbacks.rb:264:in'create\u或\u update'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active\u record/persistence.rb:37:in'save'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active\u record/validations.rb:50:in'save'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active\u record/attribute\u methods/dirty.rb:22:in'save'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/transactions.rb:241:in `保存中的块（2级）'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active\u record/transactions.rb:295:in‘阻塞输入，事务返回状态’
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active\u record/connection\u adapters/abstract/database\u语句。rb:194:in'transaction'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/transactions.rb:208:in'transaction'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active\u record/transactions.rb:293:in`with\u transaction\u returning\u status'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/transactions.rb:241:in'block in save'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active\u record/transactions.rb:252:处于“回滚”活动记录状态
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activerecord-3.1.10/lib/active_record/transactions.rb:240:in'save'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/bundler/gems/spree-22cd84cc71d9/core/lib/spree/preference_access.rb:20:in'set'
/home/nishant/voylla_网站/db/seeds.rb:13:in`'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activesupport-3.1.10/lib/active\u-support/dependencies.rb:234:in'load'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activesupport-3.1.10/lib/active\u support/dependencies.rb:234:in'block in load'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activesupport-3.1.10/lib/active\u-support/dependencies.rb:223:in'block-in-load\u-dependencity'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activesupport-3.1.10/lib/active\u-support/dependencies.rb:640:in'new\u-constants\u-in'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activesupport-3.1.10/lib/active\u-support/dependencies.rb:223:in'load\u-dependency'
/home/nishant/.rvm/gems/ruby-1.9.2-p320@voylla/gems/activesupport-3.1.10/lib/active\u-support/dependencies.rb:234:in'load'
/home/nishant/.rvm/gems/ruby-1