Don't require braintree to be always installed. Fixes #74

hc/payments/models.py

@@ -1,8 +1,14 @@
-import braintree
-
+from django.conf import settings
 from django.contrib.auth.models import User
 from django.db import models
 
+if settings.USE_PAYMENTS:
+    import braintree
+else:
+    # hc.payments tests mock this object, so tests should
+    # still be able to run:
+    braintree = None
+
 
 class SubscriptionManager(models.Manager):