Add a basic UI layer to existing ruby app

First, I am fairly new to Ruby/RoR and so you'll have to forgive me for any wrong terminology, but hopefully I'll get my point across.

I built an ruby app that I am needing to add an extremely simple UI layer using rails. Read up on a previous post of mine that explains the project thoroughly to give you good an idea of what it does. Specifically take a look at the tree outline that I pasted in so you see the existing file structure for the project.

What I need to know, is how to convert this existing project into a rails app? My experience in building something with rails has always started out with rails new app_name, but never anything like this. Any tips would be appreciated.