Implement Firebase push notifications

backend/models.py

@@ -113,6 +113,16 @@ class PushSubscription(Base):
     updated_at = Column(DateTime, default=datetime.now, onupdate=datetime.now)
 
 
+class FcmToken(Base):
+    __tablename__ = "fcm_token"
+
+    id = Column(Integer, primary_key=True, index=True)
+    user_id = Column(Integer, ForeignKey("user.id"), nullable=False, index=True)
+    token = Column(Text, nullable=False, unique=True)
+    created_at = Column(DateTime, default=datetime.now)
+    updated_at = Column(DateTime, default=datetime.now, onupdate=datetime.now)
+
+
 class Reaction(Base):
     __tablename__ = "reaction"