Repository: dj-stripe/dj-stripe
Issue: Error: Cannot resolve keyword 'customer' into field. 

All,

Cannot get past the step

`python manage.py djstripe_init_customers`

in the installation. 

Running Python 3.6.0, Django 1.11, and the latest version of dj-stripe (1.0.0).

What combination of Django version and dj-stripe version are folks successfully using at the moment? Thanks! 

Here is the traceback:
```
Traceback (most recent call last):
  File "manage.py", line 22, in <module>
    execute_from_command_line(sys.argv)
  File "/Users/jdln/.virtualenvs/djstripe/lib/python3.6/site-packages/django/core/management/__init__.py", line 363, in execute_from_command_line
    utility.execute()
  File "/Users/jdln/.virtualenvs/djstripe/lib/python3.6/site-packages/django/core/management/__init__.py", line 355, in execute
    self.fetch_command(subcommand).run_from_argv(self.argv)
  File "/Users/jdln/.virtualenvs/djstripe/lib/python3.6/site-packages/django/core/management/base.py", line 283, in run_from_argv
    self.execute(*args, **cmd_options)
  File "/Users/jdln/.virtualenvs/djstripe/lib/python3.6/site-packages/django/core/management/base.py", line 330, in execute
    output = self.handle(*args, **options)
  File "/Users/jdln/temp/dj-stripe/djstripe/management/commands/djstripe_init_customers.py", line 25, in handle
    for subscriber in get_subscriber_model().objects.filter(customer__isnull=True):
  File "/Users/jdln/.virtualenvs/djstripe/lib/python3.6/site-packages/django/db/models/manager.py", line 85, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/Users/jdln/.virtualenvs/djstripe/lib/python3.6/site-packages/django/db/models/query.py", line 781, in filter
    return self._filter_or_exclude(False, *args, **kwargs)
  File "/Users/jdln/.virtualenvs/djstripe/lib/python3.6/site-packages/django/db/models/query.py", line 799, in _filter_or_exclude
    clone.query.add_q(Q(*args, **kwargs))
  File "/Users/jdln/.virtualenvs/djstripe/lib/python3.6/site-packages/django/db/models/sql/query.py", line 1260, in add_q
    clause, _ = self._add_q(q_object, self.used_aliases)
  File "/Users/jdln/.virtualenvs/djstripe/lib/python3.6/site-packages/django/db/models/sql/query.py", line 1286, in _add_q
    allow_joins=allow_joins, split_subq=split_subq,
  File "/Users/jdln/.virtualenvs/djstripe/lib/python3.6/site-packages/django/db/models/sql/query.py", line 1164, in build_filter
    lookups, parts, reffed_expression = self.solve_lookup_type(arg)
  File "/Users/jdln/.virtualenvs/djstripe/lib/python3.6/site-packages/django/db/models/sql/query.py", line 1044, in solve_lookup_type
    _, field, _, lookup_parts = self.names_to_path(lookup_splitted, self.get_meta())
  File "/Users/jdln/.virtualenvs/djstripe/lib/python3.6/site-packages/django/db/models/sql/query.py", line 1362, in names_to_path
    "Choices are: %s" % (name, ", ".join(available)))
django.core.exceptions.FieldError: Cannot resolve keyword 'customer' into field. Choices are: date_joined, djstripe_customers, email, first_name, groups, id, is_active, is_staff, is_superuser, last_login, last_name, logentry, password, user_permissions, username
```

Changed files:
djstripe/management/commands/djstripe_init_customers.py

diff --git a/djstripe/management/commands/djstripe_init_customers.py b/djstripe/management/commands/djstripe_init_customers.py
index 53eae4a8..cbf4c0b3 100644
--- a/djstripe/management/commands/djstripe_init_customers.py
+++ b/djstripe/management/commands/djstripe_init_customers.py
@@ -22,7 +22,7 @@ class Command(BaseCommand):
 
     def handle(self, *args, **options):
         """Create Customer objects for Subscribers without Customer objects associated."""
-        for subscriber in get_subscriber_model().objects.filter(customer__isnull=True):
+        for subscriber in get_subscriber_model().objects.filter(djstripe_customers=None):
             # use get_or_create in case of race conditions on large subscriber bases
             Customer.get_or_create(subscriber=subscriber)
             print("Created subscriber for {0}".format(subscriber.email))