Thingspeak as daemon at system boot (startup) ubuntu 12.04 | GitHub Installation | Forum

Hi
I am trying to configure my own "Thingspeak" server on ubuntu 12.04 lts virtual machine. I introduced this commands on terminal (installation on clean install of ubuntu): https://github.com/other/ThingSpeak but at the final i use: rvmsudo rails server -d -b -p 80 This command let me run Thingspeak app on port 80 as a daemon. It works well, but when the server reboot (sudo reboot for example) the thingspeak server shut down and i don't want this, i want to automatically (on booting or startup) start the thingspeak server so i don't need to manually use in terminal the rvmsudo command again. How can i achieve this? Thanks a lot for your attention
PD:I try to add the command in /etc/rc.local but nothing happens, i probed with /etc/init.d but it is a directory not a file