title: Random 'concerns' folders and '.keep' files
body: <p>I am learning rails. </p>
  
  <p>Somewhere along the line, I noticed that seemingly random folders and files are appearing in my rails app's directory. In some folders there is a <code>concerns</code> folder with a <code>.keep</code> file inside it. The <code>.keep</code> file appears to be empty. In other folders there is no <code>concerns</code> folder but an empty <code>.keep</code> file is present.</p>
  
  <p>Does anyone know what the deal with these files/folders is?</p>