title: Logstash create nested field
body: <p>I have some fields from parsed string:
  string example:</p>
  
  <p><code>"testmessage 10.5 100"</code></p>
  
  <pre><code>match =&gt; { "message" =&gt; "%{GREEDYDATA:text} %{NUMBER:duraton} %{NUMBER:code)"
  </code></pre>
  
  <p>output will be the</p>
  
  <pre><code>    {
         "text": "testmessage",
         "duraton": "10.5",
         "code": "100"
      }
  </code></pre>
  
  <p>But i want to get like this:</p>
  
  <pre><code>    {
         "text": "testmessage",
         "values": {
              "duraton": "10.5",
              "code": "100"
         }
      }
  </code></pre>
  
  <p>How to create a field "values" containing nested field?</p>