better install instructions

INSTALL.md

@@ -36,3 +36,15 @@ pip install -r requirements.txt
 ```
 python manage.py runserver
 ```
+
+* to get Google Auth working:
+
+** go to https://console.developers.google.com
+
+** create an application
+
+** set up oauth2 credentials as a web application, with your origin, e.g. https://myhelios.example.com, and your auth callback, which, based on our example, is https://myhelios.example.com/auth/after/
+
+** still in the developer console, enable the Google+ API.
+
+** set the GOOGLE_CLIENT_ID and GOOGLE_CLIENT_SECRET configuration variables accordingly.
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