title: Adding field to a JSON using Circe
body: <p>I am going through the Circe documentation and can't figure out how to handle the following.</p>
  <p>I would simply like to add a field with an object inside the main JSON object.</p>
  <pre><code>{
    Fieldalreadythere: {}
    &quot;Newfield&quot; : {}
  }
  </code></pre>
  <p>I just want to add the <code>Newfield</code> in the object. To give a bit of context I am dealing with Json-ld. I just want to add a context object. @context: {}</p>
  <p>See example below:</p>
  <pre><code>{
    &quot;@context&quot;: {
      &quot;@version&quot;: 1.1,
      &quot;xsd&quot;: &quot;http://www.w3.org/2001/XMLSchema#&quot;,
      &quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;,
      &quot;foaf:homepage&quot;: { &quot;@type&quot;: &quot;@id&quot; },
      &quot;picture&quot;: { &quot;@id&quot;: &quot;foaf:depiction&quot;, &quot;@type&quot;: &quot;@id&quot; }
    },
    &quot;@id&quot;: &quot;http://me.markus-lanthaler.com/&quot;,
    &quot;@type&quot;: &quot;foaf:Person&quot;,
    &quot;foaf:name&quot;: &quot;Markus Lanthaler&quot;,
    &quot;foaf:homepage&quot;: &quot;http://www.markus-lanthaler.com/&quot;,
    &quot;picture&quot;: &quot;http://twitter.com/account/profile_image/markuslanthaler&quot;
  }
  </code></pre>
  <p>I would like to add the context object.</p>
  <p>How can I do that with Circe? The example in the official documentation mostly talk about modifying the value, but nothing to actually add a field and so on.</p>