title: GitLab Pages deployment step fails after successfull build
body: <p>I am trying to host a reveal.js presentation via gitlab pages. The repository can be found here: <a href="https://gitlab.com/JanGregor/demo-slides" rel="noreferrer">https://gitlab.com/JanGregor/demo-slides</a></p>
  
  <p>My <code>.gitlab-ci.yml</code> is fairly simple:</p>
  
  <pre><code>image: node:4.2.2
  
  pages:
    cache:
      paths:
      - node_modules/
    script:
    - npm install
    - node_modules/.bin/gulp
    artifacts:
      paths:
      - build
    only:
    - master
  </code></pre>
  
  <p>After a commit to master though, something goes wrong. The pages task itself is <a href="https://gitlab.com/JanGregor/demo-slides/-/jobs/27714275" rel="noreferrer">executed and runs just fine</a>. It even shows in the logs that my build directory has been scanned and that the artefacts have been found.</p>
  
  <p>Oddly, the subsequent <code>pages:deploy</code> task fails. It only says :</p>
  
  <blockquote>
    <p>pages failed to extract</p>
  </blockquote>
  
  <p>Any help would be greatly appreciated, since I have no clue where to look to next. The documentation itself isn't really helpful when trying to implement an deployment flow with npm.</p>
  
  <p>Thanks in advance folks !</p>