introduce new app domains

- generate domains app
- duplicate managemails.models.MailDomain as domains.models.MailDomain
- add domains app to gnuviechadmin.settings.base.LOCAL_APPS
- repair managemails.tests.test_models
- fix handling of empty results in osusers.models.GroupManager.get_next_gid and
  osusers.models.UserManager.get_next_uid

gnuviechadmin/domains/migrations/0001_initial.py

@@ -0,0 +1,36 @@
+# -*- coding: utf-8 -*-
+from south.utils import datetime_utils as datetime
+from south.db import db
+from south.v2 import SchemaMigration
+from django.db import models
+
+
+class Migration(SchemaMigration):
+
+    def forwards(self, orm):
+        # Adding model 'MailDomain'
+        db.create_table(u'domains_maildomain', (
+            (u'id', self.gf('django.db.models.fields.AutoField')(primary_key=True)),
+            ('created', self.gf('model_utils.fields.AutoCreatedField')(default=datetime.datetime.now)),
+            ('modified', self.gf('model_utils.fields.AutoLastModifiedField')(default=datetime.datetime.now)),
+            ('domain', self.gf('django.db.models.fields.CharField')(unique=True, max_length=128)),
+        ))
+        db.send_create_signal(u'domains', ['MailDomain'])
+
+
+    def backwards(self, orm):
+        # Deleting model 'MailDomain'
+        db.delete_table(u'domains_maildomain')
+
+
+    models = {
+        u'domains.maildomain': {
+            'Meta': {'object_name': 'MailDomain'},
+            'created': ('model_utils.fields.AutoCreatedField', [], {'default': 'datetime.datetime.now'}),
+            'domain': ('django.db.models.fields.CharField', [], {'unique': 'True', 'max_length': '128'}),
+            u'id': ('django.db.models.fields.AutoField', [], {'primary_key': 'True'}),
+            'modified': ('model_utils.fields.AutoLastModifiedField', [], {'default': 'datetime.datetime.now'})
+        }
+    }
+
+    complete_apps = ['domains']