a.rb

Ranking.constants
=> [:GeneratedFeatureMethods, :ClassMethods, :ConnectionSpecification, :OrmAdapter, :COLUMNS, :Statements, 
:TableDefinition, :CommandRecorder, :AttachmentContentTypeValidator, :HelperMethods, :AttachmentPresenceValidator, 
:AttachmentSizeValidator, :Defining, :Running, :SingletonMethods, :InstanceMethods, :TransactionError, 
:MacroReflection, :AggregateReflection, :AssociationReflection, :ThroughReflection, :Serializer, :ASSOCIATION_TYPES, 
:AssociationBuilderExtension, :TooManyRecords, :UNASSIGNABLE_KEYS, :InstanceMethodsOnActivation, :Middleware, 
:Association, :SingularAssociation, :CollectionAssociation, :CollectionProxy, :BelongsToAssociation, 
:BelongsToPolymorphicAssociation, :HasAndBelongsToManyAssociation, :HasManyAssociation, :HasManyThroughAssociation, 
:HasOneAssociation, :HasOneThroughAssociation, :ThroughAssociation, :Builder, :Preloader, :JoinDependency, 
:AssociationScope, :AliasTracker, :JoinHelper, :CALLBACKS, :Attribute, :ATTRIBUTE_TYPES_CACHED_BY_DEFAULT, 
:Read, :Write, :BeforeTypeCast, :Query, :PrimaryKey, :TimeZoneConversion, :Dirty, :Serialization, :DeprecatedUnderscoreRead, 
:NAME_COMPILABLE_REGEXP, :CALL_COMPILABLE_REGEXP, :AssociatedValidator, :UniquenessValidator, :Callbacks, 
:AcceptanceValidator, :ConfirmationValidator, :ExclusionValidator, :FormatValidator, :InclusionValidator, :LengthValidator, 
:NumericalityValidator, :WithValidator, :PresenceValidator, :Callback, :CallbackChain, :PermissionSet, :WhiteList, 
:BlackList, :Sanitizer, :LoggerSanitizer, :StrictSanitizer, :Error, :Default, :Named]