title: Error on travis-ci build "No Rakefile found"
body: <p>One github repo builds fine on travis, while another with almost exactly the same .travis.yaml file does not build, and gives the error</p>
  
  <pre><code>rake aborted!
  No Rakefile found (looking for: rakefile, Rakefile, rakefile.rb, Rakefile.rb)
  </code></pre>
  
  <p>I have seen some discussions about travis yaml files not dealing with tabs correctly, etc. but I have checked there are no tabs, only whitespaces. </p>
  
  <p>I have noticed that the <code>config</code> line on the travis dashboard has an entry for the repo that builds correctly </p>
  
  <p><img src="https://i.stack.imgur.com/RUFtM.png" alt="the one that works"></p>
  
  <p>while the one that doesn't build is missing that line</p>
  
  <p><img src="https://i.stack.imgur.com/5gBVX.png" alt="the one that doesn&#39;t work"></p>
  
  <p>However, they have the same yaml file more or less, so I don't understand why it doesn't work the same way.  </p>
  
  <p><a href="https://github.com/ropensci/rgbif/blob/master/.travis.yml" rel="noreferrer">The yaml for the repo that builds</a></p>
  
  <p><a href="https://github.com/ropensci/rplos/blob/master/.travis.yaml" rel="noreferrer">And the one that doesn't build  (some comments are removed, but that doesn't make a difference, I checked):</a></p>