コマンドrakedb：drop、rake db：create、およびrake db：migrateを実行しましたが、すべてが順調でした。ただし、コマンドrake db：seedを実行すると、奇妙なエラーが発生します
alex@ubuntu:~/RubymineProjects/some_project$ rake db:seed --trace
** Invoke db:seed (first_time)
** Execute db:seed
** Invoke db:abort_if_pending_migrations (first_time)
** Invoke environment (first_time)
** Execute environment
** Execute db:abort_if_pending_migrations
rake aborted!
Connection refused - connect(2)
/home/alex/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/net/smtp.rb:540:in `initialize'
/home/alex/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/net/smtp.rb:540:in `open'
/home/alex/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/net/smtp.rb:540:in `tcp_socket'
/home/alex/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/net/smtp.rb:549:in `block in do_start'
/home/alex/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/timeout.rb:68:in `timeout'
/home/alex/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/timeout.rb:99:in `timeout'
/home/alex/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/net/smtp.rb:549:in `do_start'
/home/alex/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/net/smtp.rb:519:in `start'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/mail-2.4.4/lib/mail/network/delivery_methods/smtp.rb:144:in `deliver!'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/mail-2.4.4/lib/mail/message.rb:2034:in `do_delivery'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/mail-2.4.4/lib/mail/message.rb:229:in `block in deliver'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/actionmailer-3.2.3/lib/action_mailer/base.rb:414:in `block in deliver_mail'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.3/lib/active_support/notifications.rb:123:in `block in instrument'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.3/lib/active_support/notifications/instrumenter.rb:20:in `instrument'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.3/lib/active_support/notifications.rb:123:in `instrument'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/actionmailer-3.2.3/lib/action_mailer/base.rb:412:in `deliver_mail'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/mail-2.4.4/lib/mail/message.rb:229:in `deliver'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/devise-2.1.0/lib/devise/models/confirmable.rb:128:in `send_on_create_confirmation_instructions'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.3/lib/active_support/callbacks.rb:416:in `_run__3737511161133628056__create__2350421739628145298__callbacks'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.3/lib/active_support/callbacks.rb:405:in `__run_callback'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.3/lib/active_support/callbacks.rb:385:in `_run_create_callbacks'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.3/lib/active_support/callbacks.rb:81:in `run_callbacks'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/callbacks.rb:268:in `create'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/persistence.rb:344:in `create_or_update'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/callbacks.rb:264:in `block in create_or_update'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.3/lib/active_support/callbacks.rb:425:in `_run__3737511161133628056__save__2350421739628145298__callbacks'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.3/lib/active_support/callbacks.rb:405:in `__run_callback'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.3/lib/active_support/callbacks.rb:385:in `_run_save_callbacks'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.3/lib/active_support/callbacks.rb:81:in `run_callbacks'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/callbacks.rb:264:in `create_or_update'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/persistence.rb:84:in `save'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/validations.rb:50:in `save'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/attribute_methods/dirty.rb:22:in `save'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/transactions.rb:241:in `block (2 levels) in save'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/transactions.rb:295:in `block in with_transaction_returning_status'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/connection_adapters/abstract/database_statements.rb:192:in `transaction'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/transactions.rb:208:in `transaction'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/transactions.rb:293:in `with_transaction_returning_status'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/transactions.rb:241:in `block in save'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/transactions.rb:252:in `rollback_active_record_state!'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/transactions.rb:240:in `save'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/relation/finder_methods.rb:293:in `find_or_instantiator_by_attributes'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/dynamic_matchers.rb:47:in `method_missing'
/home/alex/RubymineProjects/some_project/db/seeds.rb:42:in `<top (required)>'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.3/lib/active_support/dependencies.rb:245:in `load'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.3/lib/active_support/dependencies.rb:245:in `block in load'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.3/lib/active_support/dependencies.rb:236:in `load_dependency'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activesupport-3.2.3/lib/active_support/dependencies.rb:245:in `load'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/railties-3.2.3/lib/rails/engine.rb:520:in `load_seed'
/home/alex/.rvm/gems/ruby-1.9.3-p194/gems/activerecord-3.2.3/lib/active_record/railties/databases.rake:309:in `block (2 levels) in <top (required)>'
/home/alex/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `call'
/home/alex/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `block in execute'
/home/alex/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `each'
/home/alex/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `execute'
/home/alex/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/task.rb:158:in `block in invoke_with_call_chain'
/home/alex/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/monitor.rb:211:in `mon_synchronize'
/home/alex/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/task.rb:151:in `invoke_with_call_chain'
/home/alex/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/task.rb:144:in `invoke'
/home/alex/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/application.rb:116:in `invoke_task'
/home/alex/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block (2 levels) in top_level'
/home/alex/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `each'
/home/alex/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block in top_level'
/home/alex/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/home/alex/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/application.rb:88:in `top_level'
/home/alex/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/application.rb:66:in `block in run'
/home/alex/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
/home/alex/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/lib/rake/application.rb:63:in `run'
/home/alex/.rvm/gems/ruby-1.9.3-p194@global/gems/rake-0.9.2.2/bin/rake:33:in `<top (required)>'
/home/alex/.rvm/gems/ruby-1.9.3-p194@global/bin/rake:19:in `load'
/home/alex/.rvm/gems/ruby-1.9.3-p194@global/bin/rake:19:in `<main>'
/home/alex/.rvm/gems/ruby-1.9.3-p194/bin/ruby_noexec_wrapper:14:in `eval'
/home/alex/.rvm/gems/ruby-1.9.3-p194/bin/ruby_noexec_wrapper:14:in `<main>'
Tasks: TOP => db:seed
このエラーはどういう意味ですか？何を修正しますか？