必需文件
- yaml
- active_support/core_ext/hash/keys
- active_support/core_ext/object/blank
- active_support/key_generator
- active_support/message_verifiers
- active_support/deprecation
- active_support/encrypted_configuration
- active_support/hash_with_indifferent_access
- active_support/configuration_file
- active_support/parameter_filter
- rails/engine
- rails/autoloaders
- erb
- psych/y
命名空间