allow to override embedded frontend (#533)

docs/documentation/configuration/overview.md

@@ -97,6 +97,7 @@ web:
   expose_host_info: false
   cert_file: ""
   key_File: ""
+  frontend_filepath: ""
 
 webhook:
   url: ""
@@ -847,6 +848,14 @@ Without a valid `external_url`, the login process may fail due to CSRF protectio
 - **Environment Variable:** `WG_PORTAL_WEB_KEY_FILE`
 - **Description:** (Optional) Path to the TLS certificate key file.
 
+### `frontend_filepath`
+- **Default:** *(empty)*
+- **Environment Variable:** `WG_PORTAL_WEB_FRONTEND_FILEPATH`
+- **Description:** Optional base directory from which the web frontend is served. Check out the [building](../getting-started/sources.md) documentation for more information on how to compile the frontend assets.
+  - If the directory contains at least one file (recursively), these files are served at `/app`, overriding the embedded frontend assets.
+  - If the directory is empty or does not exist on startup, the embedded frontend is copied into this directory automatically and then served.
+  - If left empty, the embedded frontend is served and no files are written to disk.
+
 ---
 
 ## Webhook