title: Trying to start pm2-runtime with 3 instances for a MEAN application
body: <p>I am trying to start an existing MEAN stack app in a Docker container by using the following Docker command:</p>
  
  <pre><code>CMD ["pm2-runtime", "-i", "3", "npm", "--", "run-script", "start:prod"]
  </code></pre>
  
  <p>That command does start 3 PM2 instances, however it seems that the npm portion is not running the run-script part and it hangs with the following message in each instance:</p>
  
  <pre><code>Usage: npm &lt;command&gt;
  where &lt;command&gt; is one of:
      access, adduser, bin, bugs, c, cache, completion, config,
      ddp, dedupe, deprecate, dist-tag, docs, edit, explore, get,
      help, help-search, i, init, install, install-test, it, link,
      list, ln, login, logout, ls, outdated, owner, pack, ping,
      prefix, prune, publish, rb, rebuild, repo, restart, root,
      run, run-script, s, se, search, set, shrinkwrap, star,
      stars, start, stop, t, tag, team, test, tst, un, uninstall,
  </code></pre>
  
  <p>If I remove the <strong>"-i", "3"</strong> portion, it correctly starts 1 instance of the app in "fork" mode.</p>
  
  <p>Anyone know what would be the correct syntax for starting 3 instances, considering its using NPM with a run-script?</p>
  
  <p>Thank you</p>