Runner#stop raises an exception

[kleinron]

Runner#stop calls server-engine's stop method. The latter expects graceful argument, which is not provided.

As a temp workaround I redefined as follows:

module Sneakers
  class Runner
    def stop(graceful=true)
      @se.stop(graceful)
    end
  end
end

[gabrieljoelc]

@kleinron thanks for the suggestion. wanna open a PR? 🙏

[gabrieljoelc]

Closed via #409