implement adding options to hosting packages

- fix unique constraints on CustomerDiskSpaceOption and
  CustomerUserDatabaseOption to allow multiple options from the same template
  for hosting packages
- fix disk space calculation in CustomerHostingPackage
- implement hostingpackages forms AddDiskspaceOptionForm, AddMailboxOptionForm,
  AddUserDatabaseOptionForm
- implement hostingpackages.views.AddHostingOption
- add new URL pattern add_hosting_option to hostingpackages.urls
- add template hostingpackages/add_hosting_option.html
- link items on hostingpackages/customerhostingpackage_option_choices.html to
  add_hosting_option

gnuviechadmin/hostingpackages/models.py

@@ -80,7 +80,6 @@ class DiskSpaceOptionBase(models.Model):
     class Meta:
         abstract = True
         ordering = ['diskspace_unit', 'diskspace']
-        unique_together = ['diskspace', 'diskspace_unit']
         verbose_name = _('Disk space option')
         verbose_name_plural = _('Disk space options')
 
@@ -95,6 +94,8 @@ class DiskSpaceOption(DiskSpaceOptionBase, HostingOption):
     existing hosting packages.
 
     """
+    class Meta:
+        unique_together = ['diskspace', 'diskspace_unit']
 
 
 @python_2_unicode_compatible
@@ -107,7 +108,6 @@ class UserDatabaseOptionBase(models.Model):
     class Meta:
         abstract = True
         ordering = ['db_type', 'number']
-        unique_together = ['number', 'db_type']
         verbose_name = _('Database option')
         verbose_name_plural = _('Database options')
 
@@ -127,6 +127,8 @@ class UserDatabaseOption(UserDatabaseOptionBase, HostingOption):
     hosting packages.
 
     """
+    class Meta:
+        unique_together = ['number', 'db_type']
 
 
 @python_2_unicode_compatible
@@ -267,7 +269,7 @@ class CustomerHostingPackage(HostingPackageBase):
         options = CustomerDiskSpaceOption.objects.filter(hosting_package=self)
         for option in options:
             if option.diskspace_unit == min_unit:
-                diskspace += option.disk_space
+                diskspace += option.diskspace
             elif option.diskspace_unit > min_unit:
                 diskspace += (
                     DISK_SPACE_FACTORS[option.diskspace_unit][min_unit] *