Add an example local.py for use with docker-wagtail-develop

bakerydemo/settings/local.py.docker-compose-example

@@ -0,0 +1,6 @@
+from bakerydemo.settings.dev import *   # noqa
+import dj_database_url
+
+# Override settings here
+db_from_env = dj_database_url.config(conn_max_age=500)
+DATABASES['default'].update(db_from_env)