Solve Issue when deploying to heroku

[rafael]

Hi,

First let me thank you for this project. It's super awesome. I'm using it already... I was looking for something like this all day in a jenkins plugin and then I found your project and it solved my problem :)

I don't know if something changed in heroku from the time you created this project, but right now if you don't specify the node version, the application crashes trying to find zlib module (see http://stackoverflow.com/questions/11917048/heroku-cannot-find-module-zlib-in-nodejs)

I just fixed this small issue to make work with heroku out of the box :-)

Greetings!