content: from sqlalchemy import JSON, Column, ForeignKey, Index, String
  from sqlalchemy.orm import relationship
  
  from app.core.base_model import Base
  
  
  class UserPreferences(Base):
      __tablename__ = "user_preferences"
  
      user_id = Column(String, ForeignKey("users.uid"), primary_key=True)
      preferences = Column(JSON, nullable=False, default={})
  
      user = relationship("User", back_populates="preferences")
  
      __table_args__ = (Index("idx_user_preferences_user_id", "user_id"),)
  