title: jekyll serve not working without bundle exec
body: <p>I have this <code>jekyll</code> project <a href="https://github.com/mmistakes/minimal-mistakes" rel="nofollow">https://github.com/mmistakes/minimal-mistakes</a></p>
  
  <p>If I run <code>jekyll serve</code> this error is displayed.</p>
  
  <blockquote>
    <p>WARN: Unresolved specs during Gem::Specification.reset:
          listen (&lt; 3.1, ~> 3.0) WARN: Clearing out unresolved specs. Please report a bug if this causes problems. Configuration file:
    /home/kenden/Desktop/minimal-mistakes-master/_config.yml   Dependency
    Error: Yikes! It looks like you don't have jekyll-paginate or one of
    its dependencies installed. In order to use Jekyll as currently
    configured, you'll need to install this gem. The full error message
    from Ruby is: 'cannot load such file -- jekyll-paginate' If you run
    into trouble, you can find helpful resources at
    <a href="http://jekyllrb.com/help/" rel="nofollow">http://jekyllrb.com/help/</a>!  jekyll 3.1.3 | Error:  jekyll-paginate</p>
  </blockquote>
  
  <p>I already have <code>jekyll paginate</code> installed. I checked using <code>gem list</code>. However if I run <code>bundle exec jekyll serve</code> then the server starts perfectly.</p>
  
  <blockquote>
    <p>Configuration file:
    /home/kenden/Desktop/minimal-mistakes-master/_config.yml
                Source: /home/kenden/Desktop/minimal-mistakes-master
           Destination: /home/kenden/Desktop/minimal-mistakes-master/_site  Incremental build: disabled. Enable with --incremental
          Generating... 
                        done in 0.104 seconds.  Auto-regeneration: enabled for '/home/kenden/Desktop/minimal-mistakes-master' Configuration file:
    /home/kenden/Desktop/minimal-mistakes-master/_config.yml
        Server address: <a href="http://127.0.0.1:4000" rel="nofollow">http://127.0.0.1:4000</a>   Server running... press ctrl-c to stop.</p>
  </blockquote>
  
  <p>Why is <code>jekyll serve</code> not working and what is difference between <code>jekyll serve</code> and <code>bundle exec jekyll serve</code> ?</p>