similar behavior cds w bookstore cds w compose

compose/srv/swagger-ui.js

@@ -0,0 +1,10 @@
+
+// -----------------------------------------------------------------------
+// Adding Swagger UI - see https://cap.cloud.sap/docs/advanced/openapi
+const cds = require ('@sap/cds')
+try {
+  const cds_swagger = require ('cds-swagger-ui-express')
+  cds.once ('bootstrap', app => app.use (cds_swagger()) )
+} catch (err) {
+  if (err.code !== 'MODULE_NOT_FOUND')  throw err
+}