[REF]mail_activity_plan:change relation between plans and templates

mail_activity_plan/models/mail_activity_plan.py

@@ -2,7 +2,6 @@
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
 from odoo import api, fields, models, _
-from odoo.exceptions import UserError
 
 class MailActivityTemplate(models.Model):
     '''
@@ -10,16 +9,19 @@ class MailActivityTemplate(models.Model):
     '''
     _name = 'mail.activity.template'
     _description = 'Mail activity template'
+    _order = 'sequence'
 
-    mail_activity_plan_ids = fields.Many2many('mail.activity.plan', string='Activities plan', ondelete='restrict')
+    mail_activity_plan_id = fields.Many2one('mail.activity.plan', ondelete='restrict')
 
     mail_activity_type_id = fields.Many2one(
         'mail.activity.type', 'Activity Type',
         default=lambda self: self.env.ref('mail.mail_activity_data_todo'),
         ondelete='restrict'
     )
+
+    sequence = fields.Integer('Sequence', default=1, help="Used to order activities.")
     summary = fields.Char('Summary', compute="_compute_default_summary", store=True, readonly=False)
-    user_id = fields.Many2one('res.users', string='Assigned to', required=True)
+    user_id = fields.Many2one('res.users', string='Assigned to')
     note = fields.Html('Note')
 
     @api.depends('mail_activity_type_id')
@@ -38,5 +40,5 @@ class MailActivityPlan(models.Model):
     _description = 'Mail activity plan'
 
     name = fields.Char('Name', required=True)
-    mail_activity_template_ids = fields.Many2many('mail.activity.template', string='Activity template', ondelete='restrict')
+    mail_activity_template_ids = fields.One2many('mail.activity.template', 'mail_activity_plan_id', string='Template Activities')
     active = fields.Boolean(default=True)