fix env naming for ALLOWED_HOSTS and hint regarding env lists

.env.example

@@ -7,14 +7,16 @@ SECRET_KEY=put-something-awesomely-random-here
 # A comma-separated list of hostnames/IPs Django should listen to. For a
 # production setup this will be something like aura.example.org, for a dev
 # setup you might just use the default settings.
-# (default: 127.0.0.1, localhost)
+# Important: do not put spaces between commas and values!
+# (default: 127.0.0.1,localhost)
 #ALLOWED_HOSTS=
 
 # A comma-separated list of URIs where the webclients live that should be able
 # to access the steering API. In particular the dashboard. Might not be needed
 # in a production setup if steering and dashboard share the same domain. In
 # a dev setup the defaults might be just fine.
-# (default: http://127.0.0.1:8080, http://localhost:8080)
+# Important: do not put spaces between commas and values!
+# (default: http://127.0.0.1:8080,http://localhost:8080)
 #CORS_ORIGIN_WHITELIST=
 
 # The database settings.

steering/settings.py

@@ -30,7 +30,7 @@ ADMINS = ()
 MANAGERS = ADMINS
 
 # Must be set if DEBUG is False
-ALLOWED_HOSTS = env.list('HOSTNAMES', default=['127.0.0.1', 'localhost'])
+ALLOWED_HOSTS = env.list('ALLOWED_HOSTS', default=['127.0.0.1', 'localhost'])
 
 # Whitelist IPs that access the API
 CORS_ORIGIN_WHITELIST = env.list('CORS_ORIGIN_WHITELIST', default=(