new_contents: import datetime
  
  from sqlalchemy import Boolean
  from sqlalchemy import Column
  from sqlalchemy import DateTime
  from sqlalchemy import ForeignKey
  from sqlalchemy import Integer
  from sqlalchemy import String
  from sqlalchemy.ext.declarative import declarative_base
  from sqlalchemy.orm import sessionmaker
  from sqlalchemy.orm import relationship
  
  
  Base = declarative_base()
  Session = sessionmaker()
  
  
  class Agent(Base):
      __tablename__ = 'agent'
  
      id = Column(Integer(), primary_key=True)
      fqdn = Column(String(255))
      name = Column(String(255))
      busy = Boolean()
      properties = relationship('Property')
      created = Column(DateTime, default=datetime.datetime.now)
      last_seen = Column(DateTime, default=datetime.datetime.now)
  
  
  class Build(Base):
      __tablename__ = 'build'
  
      id = Column(Integer(), primary_key=True)
      agent = relationship('Agent')
      project = relationship('Project')
      success = Boolean()
      started = Column(DateTime, default=datetime.datetime.now)
      ended = Column(DateTime)
  
  
  class Project(Base):
      __tablename__ = 'project'
  
      id = Column(Integer(), primary_key=True)
      name = Column(String(255))
      vcs = relationship('VCSRoot')
      created = Column(DateTime, default=datetime.datetime.now)
  
  
  class VCSRoot(Base):
      __tablename__ = 'vcs_root'
  
      id = Column(Integer(), primary_key=True)
      name = Column(String(255))
      root_url = Column(String(255))
      created = Column(DateTime, default=datetime.datetime.now)
  
  
  class Property(Base):
      __tablename__ = 'property'
  
      id = Column(Integer(), primary_key=True)
      agent_id = Column(Integer, ForeignKey('agent.id'))
      namespace_id = Column(Integer, ForeignKey('property_namespace.id'))
      key = Column(String(255))
      value = Column(String(255))
      created = Column(DateTime, default=datetime.datetime.now)
  
  
  class PropertyNamespace(Base):
      __tablename__ = 'property_namespace'
  
      id = Column(Integer(), primary_key=True)
      properties = relationship('Property')
      name = Column(String(255))
      created = Column(DateTime, default=datetime.datetime.now)
  
subject: Add initial database models