[manual] Rename Django app from zephyr to zerver.

This needs to be deployed to both staging and prod at the same
off-peak time (and the schema migration run).

At the time it is deployed, we need to make a few changes directly in
the database:

(1) UPDATE django_content_type set app_label='zerver' where app_label='zephyr';
(2) UPDATE south_migrationhistory set app_name='zerver' where app_name='zephyr';

(imported from commit eb3fd719571740189514ef0b884738cb30df1320)

zerver/lib/create_user.py

@@ -0,0 +1,57 @@
+from __future__ import absolute_import
+
+from django.contrib.auth.models import UserManager
+from django.utils import timezone
+from zerver.models import UserProfile, Recipient, Subscription
+import base64
+import ujson
+import os
+import string
+
+# The ordered list of onboarding steps we want new users to complete. If the
+# steps are changed here, they must also be changed in onboarding.js.
+onboarding_steps = ["sent_stream_message", "sent_private_message", "made_app_sticky"]
+
+def create_onboarding_steps_blob():
+    return ujson.dumps([(step, False) for step in onboarding_steps])
+
+def random_api_key():
+    choices = string.ascii_letters + string.digits
+    altchars = ''.join([choices[ord(os.urandom(1)) % 62] for _ in range(2)])
+    return base64.b64encode(os.urandom(24), altchars=altchars)
+
+# create_user_profile is based on Django's User.objects.create_user,
+# except that we don't save to the database so it can used in
+# bulk_creates
+#
+# Only use this for bulk_create -- for normal usage one should use
+# create_user (below) which will also make the Subscription and
+# Recipient objects
+def create_user_profile(realm, email, password, active, bot, full_name, short_name, bot_owner):
+    now = timezone.now()
+    email = UserManager.normalize_email(email)
+    user_profile = UserProfile(email=email, is_staff=False, is_active=active,
+                               full_name=full_name, short_name=short_name,
+                               last_login=now, date_joined=now, realm=realm,
+                               pointer=-1, is_bot=bot, bot_owner=bot_owner,
+                               onboarding_steps=create_onboarding_steps_blob())
+
+    if bot or not active:
+        user_profile.set_unusable_password()
+    else:
+        user_profile.set_password(password)
+
+    user_profile.api_key = random_api_key()
+    return user_profile
+
+def create_user(email, password, realm, full_name, short_name,
+                active=True, bot=False, bot_owner=None,
+                avatar_source=UserProfile.AVATAR_FROM_GRAVATAR):
+    user_profile = create_user_profile(realm, email, password, active, bot,
+                                       full_name, short_name, bot_owner)
+    user_profile.avatar_source = avatar_source
+    user_profile.save()
+    recipient = Recipient.objects.create(type_id=user_profile.id,
+                                         type=Recipient.PERSONAL)
+    Subscription.objects.create(user_profile=user_profile, recipient=recipient)
+    return user_profile