model.py

from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, ForeignKey, DateTime
from datetime import datetime

Base = declarative_base()

class User(Base):
    """
    This table records the users of the site
    """
    __tablename__ = "users"
    id = Column(Integer, primary_key=True, index=True)
    first_name = Column(String(150))
    last_name = Column(String(150))
    username = Column(String(150))
    email = Column(String(150))
    password = Column(String(150))
    
class Post(Base):
    """
    A table to record all posts made by all users of the minitwitter
    """
    __tablename__ = "posts"
    id = Column(Integer, primary_key=True, index=True)
    userId = Column(Integer, ForeignKey("users.id"))
    post = Column(String(150))
    created = Column(DateTime, default=datetime.utcnow)

class Follower(Base):
    """
    This table records the following of each user, 
    UserId refers to the user been followed
    And FollowerId refers to the follower
    """
    __tablename__ = "followers"
    id = Column(Integer, primary_key=True, index=True)
    userId = Column(Integer, ForeignKey("users.id"))
    FollowerId = Column(Integer, ForeignKey("users.id"))