Include project names in the name of billing

Signed-off-by: Michal Čihař <michal@cihar.com>

weblate/billing/models.py

@@ -74,7 +74,10 @@ class Billing(models.Model):
     )
 
     def __str__(self):
-        return '{0} ({1})'.format(self.user, self.plan)
+        return '{0}: {1} ({2})'.format(
+            ', '.join([str(x) for x in self.projects.all()]),
+            self.user, self.plan
+        )
 
     def count_changes(self, interval):
         return Change.objects.filter(

weblate/billing/tests.py

@@ -69,15 +69,15 @@ class BillingTest(TestCase):
         call_command('billing_check', stdout=out)
         self.assertEqual(
             out.getvalue(),
-            'Following billings are over limit:\n * bill (test)\n'
+            'Following billings are over limit:\n * test0, test1: bill (test)\n'
         )
         self.invoice.delete()
         out = StringIO()
         call_command('billing_check', stdout=out)
         self.assertEqual(
             out.getvalue(),
-            'Following billings are over limit:\n * bill (test)\n'
-            'Following billings are past due date:\n * bill (test)\n'
+            'Following billings are over limit:\n * test0, test1: bill (test)\n'
+            'Following billings are past due date:\n * test0, test1: bill (test)\n'
         )
 
     def test_invoice_validation(self):