Add DEFAULT_URL_SCHEME setting and set to http

This setting needs to be changed if the site needs to be served over
https. Putting this here with the default value so that it's easier to
find this setting again when we need it.

http://django-subdomains.readthedocs.io/en/latest/ref/utils.html#module-subdomains.utils

writeit/settings.py

@@ -67,6 +67,10 @@
 # If you set this to False, Django will not use timezone-aware datetimes.
 USE_TZ = True
 
+# If the site is being served over https change this to 'https' so that links
+# to subdomains use the correct scheme.
+DEFAULT_URL_SCHEME = 'http'
+
 # Absolute filesystem path to the directory that will hold user-uploaded files.
 # Example: "/var/www/example.com/media/"
 MEDIA_ROOT = ''