title: Gulp not working with GitLab runner
body: <p>I want to get a GitLab runner to work on my laptop (Windows 10) but it does not execute the <code>gulp</code> commands, because <code>"gulp" is not recognized as a script</code>.</p>
  
  <p>This is my <code>.gitlab-ci.yaml</code></p>
  
  <pre><code>before_script:
    - npm install -g gulp-cli
    - npm install
  
  cache:  
    paths:
      - node_modules/
  
  stages:
    - build
  
  building:
    stage: build
    tags:
      - onpremise
    script:   
      - gulp build
  </code></pre>
  
  <p>The relevant settings of my <code>config.toml</code></p>
  
  <pre><code>executor = "shell"
  shell = "powershell"
  </code></pre>
  
  <p>(<em>If I set shell to <code>"cmd"</code> then <code>gulp build</code> is not called at all.</em>)</p>
  
  <p>And the output of my build job in GitLab</p>
  
  <pre><code>$ npm install -g gulp-cli
  C:\USERS\_SYSTEM\AppData\Roaming\npm\gulp -&gt; 
  C:\USERS\_SYSTEM\AppData\Roaming\npm\node_modules\gulp-cli\bin\gulp.js
  + gulp-cli@2.0.1
  updated 1 package in 7.67s
  $ npm install
  up to date in 11.609s
  $ gulp build
  gulp : The term "gulp" is not recognized as cmdlet, function, script file, or operable program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
  </code></pre>