Here's the `posts.py` file with the SQLAlchemy model for posts:


from sqlalchemy import Column, ForeignKey, Integer, String, Text
from sqlalchemy.orm import relationship
from sqlalchemy.sql.sqltypes import TIMESTAMP
from sqlalchemy.sql import func

from app.db import Base

class Post(Base):
    __tablename__ = "posts"

    id = Column(Integer, primary_key=True, index=True)
    title = Column(String, nullable=False)
    content = Column(Text, nullable=False)
    created_at = Column(TIMESTAMP, server_default=func.now())
    updated_at = Column(TIMESTAMP, server_default=func.now(), onupdate=func.now())
    user_id = Column(Integer, ForeignKey("users.id"), nullable=False)

    user = relationship("User", back_populates="posts")

    def __repr__(self):
        return f"Post(id={self.id}, title='{self.title}', content='{self.content[:20]}...')"

Explanation:

5. We define the columns for the `Post` model:
   - `id`: Integer primary key and index column.
   - `title`: String column that cannot be null.
   - `content`: Text column that cannot be null.
   - `created_at`: TIMESTAMP column with a default value of the current server time.
   - `updated_at`: TIMESTAMP column with a default value of the current server time and updated on each update.
   - `user_id`: Integer column that is a foreign key referencing the `id` column of the `users` table.