✨ Added PushSubscription class to manage push notification subscriptions.

app/models/__init__.py

@@ -3,4 +3,5 @@ from .pin import Pin
 from .token_data import TokenData
 from .token import Token
 from .user import User
-from .HTTPError import HTTPError
+from .HTTPError import HTTPError
+from .push import PushSubscription

app/models/push.py

@@ -0,0 +1,5 @@
+from pydantic import BaseModel
+
+class PushSubscription(BaseModel):
+    endpoint: str
+    keys: dict