Sidekiq path should be configurable

[nesaulov]

Say we have a monorepo with two separate applications in it: client and server.
Right now capistrano-sidekiq does not allow to specify where sidekiq command should be executed, instead there is a hardcoded value: release_path

capistrano-sidekiq/lib/capistrano/tasks/sidekiq.rake

Lines 180 to 182 in b290994

	within release_path do
	yield(pid_file, idx)
	end

This should be configurable i think

[nesaulov]

I will open a PR with a proposed fix