Extract a SPEC.md from current features

[asmacdo]

This project started as a POC without much consideration for expanding into a multi-user/multi-project flexible, configurable design.

Additional features are needed, which I think may benefit from some thinking about higher level architecture.

• multiple containers with various environments
• user level configuration
• per project configuration

I think we should start by developing a SPEC for what we currently do, and what we'd like to do, and consider if/how the architecture should change to improve flexibility and prevent bloat.

[yarikoptic]

I think it would be worthwhile if we get more than 1 user (me) ;)