[FIX] contract: Template lines handling (#92)

Update contract template lines handling to fix #80, and fix #59 #100

contract/models/account_analytic_contract_line.py

@@ -0,0 +1,19 @@
+# -*- coding: utf-8 -*-
+# Copyright 2017 LasLabs Inc.
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+
+from odoo import fields, models
+
+
+class AccountAnalyticContractLine(models.Model):
+
+    _name = 'account.analytic.contract.line'
+    _description = 'Contract Lines'
+    _inherit = 'account.analytic.invoice.line'
+
+    analytic_account_id = fields.Many2one(
+        string='Contract',
+        comodel_name='account.analytic.contract',
+        required=True,
+        ondelete='cascade',
+    )