title: Postgres jsonb 'NOT contains' operator
body: <p>I'm experimenting with postgres <code>jsonb</code> column types, and so far so good. 
  One common query I'm using is like this: </p>
  
  <pre><code>select count(*) from jsonbtest WHERE attributes @&gt; '{"City":"Mesa"}';
  </code></pre>
  
  <p>How do I reverse that? Is there a different operator or is it simply used as </p>
  
  <pre><code>select count(*) from jsonbtest WHERE NOT attributes @&gt; '{"City":"Mesa"}';
  </code></pre>