implement model changes

- add new domains.apps.AppConfig to allow translatable app description for
  domains app
- link domains to a customer
- extract common functionality from domains.models.MailDomain into abstract
  domains.models.DomainBase
- add separate domains.models.HostingDomain to allow for generic external
  domains
- add new hostingpackages.models.CustomerHostingPackageDomain to assign hosting
  domains to hosting packages

gnuviechadmin/domains/models.py

@@ -1,4 +1,11 @@
+"""
+This module contains models related to domain names.
+
+"""
+from __future__ import absolute_import, unicode_literals
+
 from django.db import models
+from django.conf import settings
 from django.utils.encoding import python_2_unicode_compatible
 from django.utils.translation import ugettext as _
 
@@ -6,12 +13,54 @@ from model_utils.models import TimeStampedModel
 
 
 @python_2_unicode_compatible
-class MailDomain(TimeStampedModel, models.Model):
-    domain = models.CharField(max_length=128, unique=True)
+class DomainBase(TimeStampedModel):
+    """
+    This is the base model for domains.
 
+    """
+    domain = models.CharField(_('domain name'), max_length=128, unique=True)
+    customer = models.ForeignKey(
+        settings.AUTH_USER_MODEL, verbose_name=_('customer'), blank=True,
+        null=True)
+
+    class Meta:
+        abstract = True
+
+    def __str__(self):
+        return self.name
+
+
+@python_2_unicode_compatible
+class MailDomain(DomainBase):
+    """
+    This is the model for mail domains. Mail domains are used to configure the
+    mail servers (SMTP/IMAP/POP3). Mail addresses are assigned to these mail
+    domains.
+
+    """
     class Meta:
         verbose_name = _('Mail domain')
         verbose_name_plural = _('Mail domains')
 
     def __str__(self):
         return self.domain
+
+
+@python_2_unicode_compatible
+class HostingDomain(DomainBase):
+    """
+    This is the model for hosting domains. A hosting domain is linked to a
+    customer hosting account.
+
+    """
+    maildomain = models.OneToOneField(
+        MailDomain, verbose_name=_('mail domain'), blank=True, null=True,
+        help_text=_('assigned mail domain for this domain')
+    )
+
+    class Meta:
+        verbose_name = _('Hosting domain')
+        verbose_name_plural = _('Hosting domains')
+
+    def __str__(self):
+        return self.domain