Add discord_id and profile_picture fields to User model

backend/app/models/user.py

@@ -13,6 +13,8 @@ class User(Base):
     email = Column(String(100), unique=True, index=True, nullable=False)
     full_name = Column(String(100))
     hashed_password = Column(String(200), nullable=False)
+    discord_id = Column(String(100))  # For Discord integration
+    profile_picture = Column(String(500))  # URL to profile picture
     is_active = Column(Boolean, default=True)
     is_admin = Column(Boolean, default=False)
     created_at = Column(DateTime, default=datetime.utcnow)