Created a registry based on the +PerThreadRegistry+ module for
subscriber queues. Helps limit the number of thread locals.
Merge pull request #10285 from wangjohn/subscriber_registry

Created a registry for ActiveSupport::Subscriber queues
Return a 405 response for unknown HTTP methods
Merge pull request #10299 from econsultancy/use-method-not-allowed-exception

Use MethodNotAllowed exception rather than UnknownHttpMethod
remove redundant variable
Merge pull request #10302 from vipulnsward/remove_redundant_var

Remove redundant variable
extract arrays to constants in Mapper
Merge pull request #10301 from vipulnsward/extract_in_mapper

extract arrays to constants in Mapper
applies documentation guidelines
ActiveRecord -> Active Record