title: Invalid JSON message received
body: <p>I'm trying to POST into an API I have made, and I am testing it using Postman. I am getting back a 400 Bad Request error back as a response with the message <code>Invalid JSON message received</code>.</p>
  
  <p>This is an example of the record being feedback to the user using GET.</p>
  
  <pre><code>{
      "id":3,
      "title":"Radio Etiquette Book",
      "summary":"This book provides advice on how to present a radio programme with flair.",
      "timestamp":"2016-12-22T18:18:20+0000",
      "author":{"id":1,...***},
      "reviews":
  }
  </code></pre>
  
  <p>I presume the problem is with <code>author</code> because <code>author</code> contains sub fields, such as ID, username, password and sub classes called <code>entries</code> (books created by that author), and <code>reviews</code> (reviews written by that author).</p>
  
  <p>How can I POST a new entry to avoid a 400 Bad Request error? I'm not sure which value it is, that I am posting incorrectly, but debating on whether it is actually author, and how it should be entered.</p>