Add migrations to make DB datetimes tz aware

Our models expect the datetimes to be timezone aware, however the
database itself has timezone unaware datetimes. This should reconcile
that by adding a migration to make the database timezones to be datetime
aware.

alembic/versions/56627251b8c0_make_datetimes_tz_aware.py

@@ -0,0 +1,84 @@
+"""make datetimes tz aware
+
+Revision ID: 56627251b8c0
+Revises: 6991bcb18f89
+Create Date: 2024-07-04 14:23:08.370773
+
+"""
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.dialects import postgresql
+
+
+# revision identifiers, used by Alembic.
+revision = "56627251b8c0"
+down_revision = "6991bcb18f89"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.alter_column(
+        "scans",
+        "queued_at",
+        existing_type=postgresql.TIMESTAMP(),
+        type_=sa.DateTime(timezone=True),
+        existing_nullable=True,
+        postgresql_where="queued_at AS TIME ZONE 'UTC'",
+    )
+    op.alter_column(
+        "scans",
+        "pending_at",
+        existing_type=postgresql.TIMESTAMP(),
+        type_=sa.DateTime(timezone=True),
+        existing_nullable=True,
+        postgresql_where="pending_at AS TIME ZONE 'UTC'",
+    )
+    op.alter_column(
+        "scans",
+        "finished_at",
+        existing_type=postgresql.TIMESTAMP(),
+        type_=sa.DateTime(timezone=True),
+        existing_nullable=True,
+        postgresql_where="finished_at AS TIME ZONE 'UTC'",
+    )
+    op.alter_column(
+        "scans",
+        "reported_at",
+        existing_type=postgresql.TIMESTAMP(),
+        type_=sa.DateTime(timezone=True),
+        existing_nullable=True,
+        postgresql_where="reported_at AS TIME ZONE 'UTC'",
+    )
+
+
+def downgrade() -> None:
+    op.alter_column(
+        "scans",
+        "reported_at",
+        existing_type=sa.DateTime(timezone=True),
+        type_=postgresql.TIMESTAMP(),
+        existing_nullable=True,
+    )
+    op.alter_column(
+        "scans",
+        "finished_at",
+        existing_type=sa.DateTime(timezone=True),
+        type_=postgresql.TIMESTAMP(),
+        existing_nullable=True,
+    )
+    op.alter_column(
+        "scans",
+        "pending_at",
+        existing_type=sa.DateTime(timezone=True),
+        type_=postgresql.TIMESTAMP(),
+        existing_nullable=True,
+    )
+    op.alter_column(
+        "scans",
+        "queued_at",
+        existing_type=sa.DateTime(timezone=True),
+        type_=postgresql.TIMESTAMP(),
+        existing_nullable=True,
+    )