title: Gradle - Add single file to JAR
body: <p>I have the file "license.txt" in the root directory of my project. In the jar-task, I want to add this file to the (root folder of the) JAR file.</p>
  
  <p>I tried</p>
  
  <pre><code>jar {
    from '.' include 'license.txt'
  }
  </code></pre>
  
  <p>but this <em>replaces</em> the other content (.class files) instead of <em>adding</em> a file.
  And I do not want to add the license.txt to the resources folder, because I do not want to change my project structure just because of the build tool.</p>
  
  <p>Who can help? Thank you!</p>