flask db check should pass without schema-drift

Running flask db check in the deployed environment reports differences between the SQLAlchemy models, Alembic migration history, and the live PostgreSQL schema.

## How to reproduce

`$ flask db check`

## Expected behavior

`flask db check`exits with status 0 and reports no schema changes.

## Actual behavior

schema-drift detected

## Sketch

[Notes or a checklist reflecting our understanding of the selected approach]