title: what is --ci and --no-ci options in lerna bootstrap
body: <p>I found following command in certain <code>package.json</code>.I understand <code>lerna bootstrap</code> is like <code>npm install</code>. but I couldn't figure out what is the <code>--ci</code> and <code>--no-ci</code> options of that</p>
  <p><code>lerna bootstrap --ci</code></p>
  <p><code>lerna bootstrap --no-ci</code></p>
  <p>I read lerna <a href="https://github.com/lerna/lerna/blob/v2.0.0-beta.32/README.md#flags" rel="nofollow noreferrer">read.me</a>,but I couldn't find out this kind of options.</p>
  <p>Are there any document of that ?
  Thanks</p>