add mkdocs

docs/widgets/services/watchtower.md

@@ -0,0 +1,15 @@
+---
+title: Watchtower
+description: Watchtower Widget Configuration
+---
+
+To use this widget, Watchtower needs to be configured to to [enable metrics](https://containrrr.dev/watchtower/metrics/).
+
+Allowed fields: `["containers_scanned", "containers_updated", "containers_failed"]`.
+
+```yaml
+widget:
+    type: watchtower
+    url: http://your-ip-address:8080
+    key: demotoken
+```