1) If the VM is running, stop it.
2) To forward from port 3001 on the host to port 3000 on the guest, run the following command on the host.
$ VBoxManage modifyvm "Ubuntu" --natpf1 "webrick,tcp,,3001,,3000"
3) To delete the port forwarding run:
VBoxManage modifyvm "Ubuntu" --natpf1 delete "webrick"
4) Now you can go to http://localhost:3001 on your host to hit webrick running on your VM.
The page loads very slow. Is there any way to speed it up?