new_contents: from sqlalchemy.dialects.postgresql import UUID
  from podhub.website import db
  from . import Base
  
  
  tags = db.Table(
      'tags',
      db.Column('tag_id', UUID, db.ForeignKey('tag.id')),
      db.Column('podcast_id', UUID, db.ForeignKey('podcast.id'))
  )
  
  class Podcast(Base):
      language = db.Column(db.String(80))
      subtitle = db.Column(db.String(80))
      summary = db.Column(db.Text)
      title = db.Column(db.String(80))
      rights = db.Colum(db.Text)
      link = db.Column(db.String(2048))
  
      tags = db.relationship('Tag', backref=db.backref('podcasts',
                                                       lazy='dynamic'),
                             lazy='dynamic', secondary=tags)
      image = db.relationship('Image', backref='podcast', lazy='dynamic',
                              uselist=False)
  
      publisher_id = db.Column(UUID, db.ForeignKey('publisher.id'))
      author_id = db.Column(UUID, db.ForeignKey('author.id'))
  
      def __init__(self, title, link=None, publisher_id=None, author_id=None,
                   image=None, subtitle=None, summary=None, language=None,
                   rights=None):
          self.title = title
          self.subtitle = subtitle
          self.summary = summary
          self.language = language
          self.rights = rights
  
          self.publisher_id = publisher_id
          self.author_id = author_id
          self.image = image
  
  
  class Tag(Base):
      name = db.Column(db.String(80))
  
      def __init__(self, name):
          self.name = name
  
  
  class Image(Base):
      name = db.Column(db.String(80))
      href = db.Column(db.String(2048))
      podcast_id = db.Column(UUID, db.ForeignKey('podcast.id'))
  
      def __init__(self, href, name=None, podcast_id=None):
          self.name = name
          self.href = href
          self.podcast_id = podcast_id
  
subject: add content type models