add https setting to docs

docs/installation.rst

@@ -146,6 +146,7 @@ To get your instance running in production you need to create your production se
         SESSION_COOKIE_SECURE = True
         SECURE_HSTS_SECONDS = 31536000
         SECURE_HSTS_INCLUDE_SUBDOMAINS = True
+        ACCOUNT_DEFAULT_HTTP_PROTOCOL = 'https'
 
     # Url for serving assets like CSS, JavaScript and images
     STATIC_URL = '/static/'