title: Dockerfile copy keep subdirectory structure
body: <p>I'm trying to copy a number of files and folders to a docker image build from my localhost.</p>
  <p>The files are like this:</p>
  <pre><code>folder1/
      file1
      file2
  folder2/
      file1
      file2
  </code></pre>
  <p>I'm trying to make the copy like this:</p>
  <pre><code>COPY files/* /files/
  </code></pre>
  <p>However, all of the files from <code>folder1/</code> and <code>folder2/</code> are placed in <code>/files/</code> directly, without their folders:</p>
  <pre><code>files/
      file1
      file2
  </code></pre>
  <p>Is there a way in Docker to keep the subdirectory structure as well as copying the files into their directories?</p>