New Rails apps come with this class already, the job generator creates
it for every new job and Rubocop requires it as well. Let's make our
lives easier and use the same structure as other Rails projects. This
class may be handy one day.
Sidekiq doesn't have any features to limit memory usage or execution
time. We need a separate process for this. Forking avoids the boot time
of a fresh process and copy-on-write ensures minimal memory overheads.
