title: Flask-Admin view with many to many relationship model
body: <p>I have this basic flask-admin set-up with users and user roles</p>
  
  <pre><code>class Role(db.Model, RoleMixin):
      id = db.Column(db.Integer(), primary_key=True)
      name = db.Column(db.String(80), unique=True)
      description = db.Column(db.String(255))
  
  class User(db.Model, UserMixin):
      id = db.Column(db.Integer, primary_key=True)
      email = db.Column(db.String(255), unique=True)
      password = db.Column(db.String(255))
      active = db.Column(db.Boolean())
      confirmed_at = db.Column(db.DateTime())
      roles = db.relationship('Role', secondary="roles_users",
                              backref=db.backref('users', lazy='dynamic'))
  class RolesUsers(db.Model):
      __tablename__="roles_users"
      id = db.Column(db.Integer(), primary_key=True)
      user_id = db.Column(db.Integer(), db.ForeignKey('user.id', ondelete='CASCADE'))
      role_id = db.Column(db.Integer(), db.ForeignKey('role.id', ondelete='CASCADE'))
  </code></pre>
  
  <p>I want to display user view that will show roles specific user has. With one to many relationship I would do somethin like this</p>
  
  <pre><code>class UserView(ModelView):
      column_hide_backrefs = False
  
  class Role(db.Model, RoleMixin):
      ...
      def __str__(self):
          return self.name
  </code></pre>
  
  <p>How would I do this with many to many relationship</p>