Use COMMON_PROJECT_URL as host for document link

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

HISTORY.rst

@@ -265,6 +265,9 @@
 * Show a null mailer backend if there is backend with an
   invalid path. Due to the app full path change, existing
   mailer setups need to be recreated. 
+* The document link URL when mailed is now composed of the
+  COMMON_PROJECT_URL + document URL instead of the Site
+  domain.
 
 3.1.11 (2019-04-XX)
 ===================

docs/releases/3.2.rst

@@ -575,6 +575,9 @@ Other changes
 * Show a null mailer backend if there is backend with an
   invalid path. Due to the app full path change, existing
   mailer setups need to be recreated. 
+* The document link URL when mailed is now composed of the
+  COMMON_PROJECT_URL + document URL instead of the Site
+  domain.
 
 
 Removals

mayan/apps/mailer/models.py

@@ -3,7 +3,8 @@ from __future__ import unicode_literals
 import json
 import logging
 
-from django.contrib.sites.models import Site
+from furl import furl
+
 from django.core import mail
 from django.db import models, transaction
 from django.template import Context, Template
@@ -11,6 +12,8 @@ from django.utils.html import strip_tags
 from django.utils.module_loading import import_string
 from django.utils.translation import ugettext_lazy as _
 
+from mayan.apps.common.settings import setting_project_url
+
 from .classes import NullBackend
 from .events import event_email_sent
 from .managers import UserMailerManager
@@ -174,10 +177,9 @@ class UserMailer(models.Model):
         Send a document using this user mailing profile.
         """
         context_dictionary = {
-            'link': 'http://%s%s' % (
-                Site.objects.get_current().domain,
+            'link': furl(setting_project_url.value).join(
                 document.get_absolute_url()
-            ),
+            ).tostr(),
             'document': document
         }