Updated Admin API Reference (markdown)

Admin-API-Reference.md

@@ -6,6 +6,9 @@ In order to use this interface, you need to enable the admin interface:
 var server = FluentMockServer.StartWithAdminInterface();
 ```
 
+## API definition
+A Swagger 2.0 definition can be found [here](https://app.swaggerhub.com/apis/StefHeyenrath/WireMock/1.0.4.8).
+
 The following interfaces are supported:
 ## /__admin/settings
 The global settings from the mock service.