[manual] Rename manage.py subscribe_new_users to process_signups.

The old name was very confusing, and this fits the convention of "the
processor for the signups" queue a la "process_user_activity".

This requires doing a

supervisorctl stop humbug-workers:humbug-events-subscribe-new-users
puppet apply

to deploy the supervisord configuration changes and properly restart
the signups queue.

(imported from commit 0ee2dad837142afa64025446e22956709771a192)

zephyr/management/commands/process_signups.py

@@ -0,0 +1,23 @@
+from __future__ import absolute_import
+
+from postmonkey import PostMonkey
+from django.core.management.base import BaseCommand
+from django.conf import settings
+
+from zephyr.lib.queue import SimpleQueueClient
+
+class Command(BaseCommand):
+    pm = PostMonkey(settings.MAILCHIMP_API_KEY, timeout=10)
+
+    def subscribe(self, ch, method, properties, data):
+        self.pm.listSubscribe(
+                id=settings.HUMBUG_FRIENDS_LIST_ID,
+                email_address=data['EMAIL'],
+                merge_vars=data['merge_vars'],
+                double_optin=False,
+                send_welcome=False)
+
+    def handle(self, *args, **options):
+        q = SimpleQueueClient()
+        q.register_json_consumer("signups", self.subscribe)
+        q.start_consuming()