Is there any way to override DATABASE_URL so I can determine which db to run migration for?

## I'm submitting a...

- [ ] Bug report
- [ ] Feature request
- [x ] Question

## Current behavior

My app recently got a new db created to have specific migrations run on it. But because of `DATABASE_URL`, I cannot set database.json or .db-migraterc to set multiple db to use `db-migrate -e `

`db-migrate` ignores database.json and .db-migraterc when `DATABASE_URL` is present in env variables. I cannot take that value out as other scripts still depend on it.

How do I run different migrations on different dbs?

## Expected behavior

Being able to run different migrations on different dbs

## Environment

db-migrate version: 0.11


Additional information:

- Node version: 10  

- Platform: Linux