• active_support/core_ext/array/access
• active_support/core_ext/enumerable
• active_support/core_ext/module/attribute_accessors
• active_support/actionable_error
• active_record/migration/pending_migration_connection

• 模組 ActiveRecord
• 模組 ActiveRecord::ConnectionHandling
• 模組 ActiveRecord::Tasks
• 模組 ActiveRecord::VERSION
• 模組 ActiveSupport
• 類別 ActiveRecord::EnvironmentMismatchError
• 類別 ActiveRecord::IrreversibleMigration
• 類別 ActiveRecord::Migration
• 類別 ActiveRecord::Migration::CheckPending
• 類別 ActiveRecord::MigrationContext