title: MySQL, json, JSON_ARRAY_APPEND - why will append not work on 5.7.13?
body: <p>How on earth do I insert data into a json mysql field.</p>
  
  <p>I can create a record</p>
  
  <pre><code>INSERT INTO git_object (user_id,git_meta,last_update) VALUES ('11111','[{"host": "a", "id": "1"}]',(select now()));
  </code></pre>
  
  <p>How do I append to the array.  </p>
  
  <pre><code>SELECT JSON_ARRAY_APPEND(git_meta, '$', '{"host": "b"}') FROM git_object where user_id='11111'
  </code></pre>
  
  <p>I tried the above.  What do I get with the below?</p>
  
  <pre><code>SELECT * FROM git_object;
  
  '[{"id": "1", "host": "a"}]'
  </code></pre>
  
  <p>What am I doing wrong</p>
  
  <p>MySQL Version '5.7.13'</p>