odoo/addons/website_event_sale/models/product.py

# -*- coding: utf-8 -*-
from openerp.osv import osv, fields

# defined for access rules
class product(osv.osv):
    _inherit = 'product.product'
    _columns = {
        'event_ticket_ids': fields.one2many('event.event.ticket', 'product_id', 'Event Tickets'),
    }