PostgreSQL support

[Lanhild]

Hello @girish
I've opened a PR to add PostgreSQL support for Open WebUI, since they've added it in v0.1.122.

They don't have a migration guide from SQLite to PostgreSQL, but a kind contributor gave me a script to migrate it, it's in the PR.

Feel free to take a look.

[girish]

@Lanhild awesome, thanks. Will take a look.

[Lanhild]

@girish I updated my PR, it's ready for merging now.

Any reason why the app is still marked as "Unstable" in the store? We have tests and the package seems to respect Cloudron's standards.

I think it could be "Stable" after my PR.

[girish]

@Lanhild thanks, will check it out. Apps using sqlite cannot be considered stable until we figure a proper backup strategy. Cloudron's backup strategy is to copy files and this doesn't work well with databases in the data directory. The data can be inconsistent.

Also, given no automatic migration from sqlite to postgres, we might have to publish a completely new package