refactor: migrate from sea-orm to sqlx

[vohoanglong0107]

This is the first step to migrate from sea-orm to sqlx. All sea-orm models have been removed. All interaction with the postgres database through raw sql string is defined in module database/operations.
The tests are expected to fail in this PR, because all those test share the same database connection. A new PR will be raised later to fix those tests by using sqlx::test, allowing each test to have its own database.

[Kobzol]

Looks very good! Had a quick look and left a few comments.

[Kobzol]

LGTM, but we can't merge with tests failing. So either you need to comment out the tests in CI for now, or fix tests in this PR.

Btw, the Dockerfile needs updating, as it copies a directory that doesn't exist anymore.

[Kobzol]

To avoid having to commit the .sqlx directory created by cargo sqlx prepare, I think that the easier thing would be to spin up a Postgres instance in our CI tests and export a DATABASE_URL variable pointing to them.

It can be done with the services key: https://docs.github.com/en/actions/using-containerized-services/creating-postgresql-service-containers#running-jobs-in-containers

[vohoanglong0107]

Got it. Once tried the approach of committing the .sqlx directory, I soon regreted it though.

[vohoanglong0107]

Since the tests fix is straightforward (by changing #[tokio::test] to #[sqlx::test] and handling the pool), I have also included the fix to this PR

[Kobzol]

Could you please also update docs/development.md? We should document the switch to sqlx and perhaps also prepare some guide for developers how to setup Postgres, i.e. with a simple docker-compose.yml file, and also the .env file so that compilation even works. Thanks!

[vohoanglong0107]

Do you think we should add a docker-compose.yaml file at the root of the project? That way we just need to add instructions on running the development environment instead of having to include the docker-compose.yaml content within the docs

[Kobzol]

Yeah, I also thought that it might be a good idea, to make it simpler for potential contributors to get the codebase working. While we're at it, I would also add the .env file (or at least .env.sample) with the connection string hardcoded for the Postgres configuration from the docker-compose.yml file.

[Kobzol]

Good! I think that the only change left is to add a CI step that checks on CI that .sqlx is updated.

[Kobzol]

Awesome! This looks really great, thanks a lot for the hard work! I think that now the DB side is much cleaner, and makes it easier for us to understand exactly what queries we are running against the DB.

[vohoanglong0107]

Haha, I have to admit, I was surprised that using raw sql string removed roughly 300 LOC from bors.

BTW, is there something wrong with the CI checks? It keeps being queued and hasn't even started yet.

[Kobzol]

Looks like some GHA bug (https://www.githubstatus.com/). The workflows have finished, but the status hasn't been updated yet.