Note: any update to the enum below should be reflected in ValidStatuses and the database enum `workflow_status`.

Note: any update to the enum below should be reflected in ValidStatuses and the database enum `workflow_status`.

Note: any update to the enum below should be reflected in ValidStatuses and the database enum `workflow_status`.

Note: any update to the enum below should be reflected in ValidStatuses and the database enum `workflow_status`.

Note: any update to the enum below should be reflected in ValidStatuses and the database enum `workflow_status`.

`DBStore` is a postgres-backed data store that persists workflow progress.