Refresh older sub first + save subscriptions

breadtube_bot/discord_manager.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 from dataclasses import asdict, dataclass, is_dataclass
+from datetime import datetime
 from enum import Enum
 import json
 import random
@@ -22,6 +23,8 @@ class ApiEncoder(json.JSONEncoder):
             return asdict(o)  # type: ignore
         if isinstance(o, Enum):
             return o.value
+        if isinstance(o, datetime):
+            return o.isoformat()
         return super().default(o)