Update directory structure

Author: LukeTowers

architecture/introduction.md

@@ -20,21 +20,23 @@ MyWinterProject/
 |   |-- backend/         # The Backend module
 |   |-- cms/             # The CMS module
 |   `-- system/          # The System module
+|-- node_modules/      # (optional) Frontend vendor files managed by NPM / Yarn
 |-- plugins/           # Plugins
 |-- storage/           # Local storage directory
 |   |-- app/             # Application storage, such as media and uploads
 |   |-- cms/             # CMS auto-generated system files
 |   |-- framework/       # System and cache files generated by the Laravel framework
 |   |-- logs/            # Error and message log storage
 |   `-- temp/            # Temporary file storage
-|-- tests/             # Automated tests
 |-- themes/            # Themes
-|-- vendor/            # Vendor files managed by Composer
+|-- vendor/            # PHP vendor files managed by Composer
 |-- artisan            # CLI entrypoint
-|-- composer.json      # Composer project file (managing dependencies)
+|-- composer.json      # Composer project file (managing PHP dependencies)
 |-- composer.lock      # Composer lock file (info on currently installed packages)
 |-- index.php          # Web request entrypoint
-`-- phpunit.xml        # PHPUnit configuration for unit test
+|-- package.json       # (optional) Node project file (managing frontend dependencies)
+|-- package.lock       # (optional) Node lock file (info on currently installed frontend packages)
+`-- phpunit.xml        # (optional) PHPUnit configuration for running automated testing suites
 ```
 
 ### Themes