install as specific user

[Thermatix]

I've tried to fork and add this myself but I honestly don't know what I'm doing (it's not particularly obvious tbh), what looks like should work doesn't. Is this already a feature? if so how or could you please add this.

I need this so I can install ruby onto a deployment machine without breaking the ruby that gets installed with chef (I plan to have a user just for running my app and only it's path will contain the ruby stuff I need to get the app running)