Add login to bookshop Vue.js app (#358)

bookshop/srv/user-service.js

@@ -1,4 +1,9 @@
 const cds = require('@sap/cds')
-module.exports = cds.service.impl((srv) => {
-  srv.on('READ', 'me', ({ tenant, user, locale }) => ({ id: user.id, locale, tenant }))
-})
+module.exports = class UserService extends cds.Service { init(){
+  this.on('READ', 'me', ({ tenant, user, locale }) => ({ id: user.id, locale, tenant }))
+  this.on('login', (req) => {
+    if (req.user._is_anonymous)
+      req._.res.set('WWW-Authenticate','Basic realm="Users"').sendStatus(401)
+    else return this.read('me')
+  })
+}}