No URLMap entries found in application configuration for a Node.JS application

I am trying to deploy a node.js app to appEngine but he doesn't seem to like my app.yaml.

D:\projects\Personal\Project>gcloud app deploy
ERROR: (gcloud.app.deploy) An error occurred while parsing file: [D:\projects\Personal\Project\app.yaml]
No URLMap entries found in application configuration
  in "D:\projects\Personal\Project\app.yaml", line 10, column 12

Here's the app.yaml:

runtime: nodejs
env: standard

skip_files:
 - ^node_modules$

env_variables:
  USER: 'dbUser'
  PASSWORD: 'DBPass'
  DB: 'URI to DB'

Am I missing something here? Could it be that it's because of my folder structure?

I have following structure: - client - server ---- server.js - app.yaml

So the app.yaml is not in the server folder as otherwise it doesn't include the client folder...

via Passero