Add Docker

[jayvarner]

Dockerize the Rails app. I'll send you the sensitive parts that need to be added using build secrets.

[jayvarner]

Currently, the app is running on Ruby 3.1.2 and Rails 6.1. Not a requirement, but it would be good to update those. The current app uses Rails's custom credentials. This is good, but it would be better to use the build secrets so we can have a common way across apps.