This is an app that uses Rails in API mode, ActiveAdmin, and React on the frontend. It's based on this post.
I'm sure my React code in here could use some cleanup but I was just excited to give a project like this a try and banged it out exactly to the instructions. I think this model will likely provide a base for an upcoming project I've been thinking about that tracks goal progress using a variety of metrics depending on the type of project.
You can see the deployed app here (while I keep the dyno up).