title: Add a dependency in a project using gem
body: <p>I am having a problem when I use Jekyll to build a website and host it on github. The website uses a relative path dependency <a href="https://github.com/benbalter/jekyll-relative-links" rel="nofollow noreferrer">jekyll-relative-links</a>, but this dependency is installed on the local disk: </p>
  
  <blockquote>
    <p>/Users/xxx/.rvm/gems/ruby-2.5.1/gems/jekyll-relative-links-0.5.3</p>
  </blockquote>
  
  <p>I will not find this dependency when I push the site onto github, so I would like to ask if I can install this dependency in the project. Thanks.</p>