text: import sys
  from sqlalchemy import Column, ForeignKey, Integer, String
  from sqlalchemy.ext.declarative import declarative_base
  from sqlalchemy.orm import relationship
  from sqlalchemy import create_engine
  
  Base = declarative_base()
  
  
  class User(Base):
  	"""Table of Users"""
  
  	__tablename__ = 'user'
  
  	name = Column(String(250), nullable = False)	
  	id = Column(Integer, primary_key = True)
  	email = Column(String(250), nullable = False)
  	picture = Column(String(500))
  
  	@property
  	def serialize(self):
  		#returns object data in easily serializeable format
  		return {
  			'username': self.name,
  		}
  
  
  class Activities(Base):
  	"""Table of Activities that includes the id of the most recent user to edit"""
  
  	__tablename__ = 'activities'
  	
  	name = Column(String(80), nullable = False)	
  	id = Column(Integer, primary_key = True)
  	user_id = Column(Integer, ForeignKey('user.id'))
  	user = relationship(User)
  
  	@property
  	def serialize(self):
  		#returns object data in easily serializeable format
  		return {
  			'activity_name': self.name,			
  			'most_recent_editor': self.user.name,
  			'most_recent_editor_id': self.user_id,
  		}
  
  
  class Subcategories(Base):
  	"""Table of Subcategories that includes the id of the most recent user to edit"""
  
  	__tablename__ = 'subcategories'
  
  	name = Column(String(80), nullable = False)	
  	id = Column(Integer, primary_key = True)
  	activity_id = Column(Integer, ForeignKey('activities.id'))
  	activity = relationship(Activities)
  	user_id = Column(Integer, ForeignKey('user.id'))
  	user = relationship(User)
  	
  	@property
  	def serialize(self):
  		#returns object data in easily serializeable format
  		return {
  			'activity_name': self.activity.name,
  			'subcategory': self.activity.name,			
  			'most_recent_editor': self.user.name,
  			'most_recent_editor_id': self.user_id,
  		}
  
  
  ###### insert at end of file #####
  
  engine = create_engine(
  	'sqlite:///categories.db')
  
  Base.metadata.create_all(engine)