title: Cannot start rails server
body: <p>I tried to <code>rails server</code></p>
  
  <blockquote>
    <blockquote>
      <p>= Could not find rake-12.0.0 in any of the sources
      Run bundle install to install missing gems.</p>
    </blockquote>
  </blockquote>
  
  <p>I tried to <code>bundle update/ install</code>
  It goes to the error msg below .</p>
  
  <p><a href="https://i.stack.imgur.com/mimaU.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/mimaU.png" alt="enter image description here"></a></p>