Support installation into existing database

We’d like to install redash into an extant application postgres database, rather than creating a separate database just for redash. We’re currently deploying with aws rds, and minimizing the additional costs associated for a separate rds installation just for redash seems like a significant win to us.

We’ve worked through the bits needed to make this happen (redash tables with namespace/schema), and create_db checks for extant installation.

Curious if there interest in the same from others.