Not going to argue your decision, the process of splitting up is also a chance to change the platform. We do a lot of non-Rails Ruby-work and did implement Mic

Not going to argue your decision, the process of splitting up is also a chance to change the platform. We do a lot of non-Rails Ruby-work and did implement Microservice-Architectures in it and found it rather unproblematic. The trick is not to start with a full-stack and build down, but to start with a small kernel of an app, deploy it, add something, deploy it, iterate, iterate, iterate.