We actually have a relay (https://github.com/remind101/empire/tree/master/relay) service that can be run alongside Empire that acts as a proxy to interactive Docker sessions. It's a bit of an experiment right now and something we'd like to solve better in the future, but it allows you to run containers with `emp run <command> -a <app>`.
Interesting! We are in a similar situation to where you were, with a bigish app on Heroku which we are keen to move over to EC2 to join the rest of our infrastructure, definitely keen to see how empire develops
