fix: add sessions.last_seen_at migration 0004

migrations/versions/0004_session_last_seen.py

@@ -0,0 +1,20 @@
+"""add session last_seen_at
+Revision ID: 0004
+Revises: 0003
+"""
+
+import sqlalchemy as sa
+from alembic import op
+
+revision = "0004"
+down_revision = "0003"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.add_column("sessions", sa.Column("last_seen_at", sa.DateTime(timezone=True), nullable=True))
+
+
+def downgrade() -> None:
+    op.drop_column("sessions", "last_seen_at")