If we create nested (namespaced) rails engine such like bukkits-admin,
`bin/rails g scaffold User name:string age:integer`
will create
`bukkits-admin/app/controllers/bukkits/users_controller.rb`
but it should create
`bukkits-admin/app/controllers/bukkits/admin/users_controller.rb`.
In #6643, we changed `namespaced_path` as root path
because we supposed application_controller is always in root
but nested rails engine's application_controller will not.
ActiveJob jobs now inherit from ApplicationJob by default.
However, when updating to Rails 5 from the old Rails,
since there is a possibility that ApplicationJob does not exist.
* Jobs generated now inherent from ApplicationJob
* ApplicationJob inherents from ActiveJob::Base
* Added entry to changelog
Signed-off-by: Jeroen van Baarsen <jeroenvanbaarsen@gmail.com>