Finalized database router support

[p-r-a-v-i-n]

Fixes #6

[RealOrangeOne]

Question: Why are you forcing this to use the writer connection? Django should route the below .count and .delete to the right place automatically.

[p-r-a-v-i-n]

Thanks for spotting.

def test_prune_dry_run_uses_write_router_database(self) -> None:
        result = test_tasks.noop_task.enqueue()

        DBTaskResult.objects.using("secondary").filter(id=result.id).update(
            status=TaskResultStatus.SUCCESSFUL,
            finished_at=timezone.now(),
        )

        stdout = StringIO()
        call_command(
            "prune_db_task_results",
            verbosity=3,
            min_age_days=0,
            dry_run=True,
            stdout=stdout,
        )

        self.assertEqual(DBTaskResult.objects.using("secondary").count(), 1)
       self.assertIn("Would delete 1 task result(s)", stdout.getvalue())

In this testcase I was calling prune_db_task_results command . so according the router setting it will fetch results from default database. In the test i suppose to show prune command output that there is 1 task would delete which from secondary database.

when i ran the prune_db_task_results command it will select db_for_read database to retrive the task results from default db where no records were created or present. so i wanted it should show 1 task to be deleted , that's why i explictly wrote. so it was wrong.