Add TIME_ZONE to the Heroku deploy config options.

README.md

@@ -329,10 +329,9 @@ be deployed and run.
 
 See also [Django's documentation on the SECRET_KEY setting](https://docs.djangoproject.com/en/1.11/ref/settings/#secret-key).
 
-
 ### `TIME_ZONE`
 
-Default: Etc/UTC
+*Default: Etc/UTC*
 
 The time zone to use for the instance. See [List of tz database time zones](https://en.wikipedia.org/wiki/List_of_tz_database_time_zones)
 for all possible values.

app.json

@@ -26,12 +26,16 @@
     ],
     "env": {
         "DJANGO_SETTINGS_MODULE": {
-            "description": "We have a prebuilt config for Heroku",
+            "description": "A prebuilt configuration for Heroku.",
             "value": "babybuddy.settings.heroku"
         },
         "SECRET_KEY": {
-            "description": "Used for the Django auth system",
+            "description": "Used for the auth system.",
             "generator": "secret"
+        },
+        "TIME_ZONE": {
+            "description": "Sets the instance time zone.",
+            "value": "Etc/UTC"
         }
     },
     "scripts": {