Add directions for handling settings to README

README.md

@@ -84,6 +84,27 @@ Push the changes to the repo with `git push`
 
 If you need to overwrite live configuration (only after confirming you've committed any parts you want to keep) you can use ahoy for that too with `deploy-site-force`.
 
+### Drupal settings file management
+
+The Drupal settings files are also managed by Drutopia. On each deploy, the file is generated and replaces the `settings.local.php` that is on the server with whatever settings will match the Drutopia configuration. Therefore, in order to add settings, you must edit the vault settings using:
+
+```
+ahoy vault-edit
+```
+
+Look for the Yaml section for agaric_live, or agaric_test, as appropriate, and edit the php_settings_code section to add items to that site's setting overrides. For example:
+
+```
+      ...
+      online: True
+      php_settings_code: |2
+        $settings['super_secret'] = p@ssw0rd;
+        $config['life.answer'] = 42;
+      server_aliases:
+        - agaric.com
+      ...
+```
+
 ## Code Hightlight.
 
 The [prism.js](https://prismjs.com/) library was added in the site and can be used like this: