Add required installed django apps to README

Author: stefanw

README.md

@@ -23,7 +23,14 @@ Add `datashow` to your `INSTALLED_APPS` in `settings.py`:
 ```python
 INSTALLED_APPS = [
     ...
+    "django.contrib.auth",
+    "django.contrib.contenttypes",
+    "django.contrib.sessions",
+    "django.contrib.humanize",  # for number formatting
+    ...
+
     'datashow',
+
     ...
 ]
 ```
@@ -40,7 +47,6 @@ urlpatterns = [
 ]
 ```
 
-
 ## Settings
 
 You can configure the following settings in your `settings.py`: