feat(bot): Add bans migration script.

migrate_bans.py

@@ -0,0 +1,24 @@
+from datetime import datetime
+
+import csv
+
+import asyncio
+
+from payphone.db import setup, models
+
+
+async def main():
+    await setup.init()
+
+    with open("bans.csv", "r", encoding="latin-1") as f:
+        reader = csv.reader(f)
+
+        for row in reader:
+            user_id = int(row[1])
+            reason = row[2].strip()[:500]
+            expires = datetime.fromisoformat(row[9].strip()) if row[9].strip() else None
+
+            await models.Ban.create(user_id=user_id, reason=reason, expires_at=expires)
+
+
+asyncio.get_event_loop().run_until_complete(main())