Update README.md

README.md

@@ -103,6 +103,8 @@ You can run either all of your tests or a single testsuite with the following co
 
 You can configure certain things by creating a `config.touchstone.php` file in the root of your project.
 
+#### Directories For Tests
+
 Here's how to set the directories for where your tests are located:
 
 ```php
@@ -118,6 +120,8 @@ return [
 ];
 ```
 
+#### Plugins
+
 Here's how to load plugins which are loaded before each test.
 
 This means for a plugin like ACF (Advanced Custom Fields) you can use functions like `get_field()` in your code and it won't break your tests.
@@ -143,6 +147,21 @@ return [
 bin/plugins
 ```
 
+#### Theme
+
+Here's how to load a theme which is active for each test.
+
+```php
+<?php
+# config.touchstone.php
+
+return [
+    'theme' => [
+        'root' => dirname(__FILE__) . '/../../themes/twentytwentyone',
+    ],
+];
+```
+
 ---
 
 ## Composer Scripts