title: Is it possible to find common words in specific Lucene documents?
body: <h2><strong>For example:</strong></h2>
  
  <pre><code>doc1 = "I got the new Apple iPhone 8";
  doc2 = "have you seen the  new Apple iPhone 8?";
  doc3 = "the Apple iPhone 8 is out";
  doc4 = "another doc without the common words";
  
  find_commons(["doc1", "doc2", "doc3", "doc4"]);
  </code></pre>
  
  <p><strong>results:</strong> <code>{{"doc1", "doc2", "doc3"}, {"Apple", "iPhone"}}</code> or something similar</p>
  
  <p><strong>Other question:</strong> is there a better library/system to achieve this using Lucene's data?</p>