What's the best practice for adding db-migrate to a project with an existing database?

## I'm submitting a...
- [ ] Bug report
- [ ] Feature request
- [x] Question

## Current behavior
db-migrate works great if you're greenfielding a new project. but my project is already live and has a database with existing schema and data. what's the recommended approach for adding db-migrate to this project?

related https://github.com/db-migrate/node-db-migrate/issues/604#issuecomment-1438955056

## Expected behavior
I expect clear guidance\docs on integrating db-migrate with live projects that already have schema and data. Alternatively, I expect that if db-migrate isn't suitable for projects that already have schema and data, the docs\README make that clear instead.

## Minimal reproduction of the problem with instructions
NA

## What is the motivation / use case for changing the behavior?
NA

## Environment

db-migrate version: latest


Additional information:

- Node version: LTS

- Platform:  linux

Others: