title: Decode JSON with unknown structure
body: <p>I want to get a string that represents a json like this one:</p>
  <pre><code>{ &quot;votes&quot;: { &quot;option_A&quot;: &quot;3&quot; } }
  </code></pre>
  <p><strong>and include a &quot;count&quot; key in it</strong> so it ends like this:</p>
  <pre><code>{ &quot;votes&quot;: { &quot;option_A&quot;: &quot;3&quot; }, &quot;count&quot;: &quot;1&quot; }
  </code></pre>
  <p>This is why I planned to convert it to json so I could add the count and then
  make it a string again. <strong>The problem is I don't know the structure of that
  JSON</strong>, so I can't use <code>json.Unmarshal(in, &amp;myStruct)</code> because that struct
  varies. How can I do this?</p>