title: wordpress rest api acting like no data is sent
body: <p>I am trying to create a post with the wordpress rest api. With curl and postman I get the following response.</p>
  
  <pre><code>{"code":"empty_content","message":"Content, title, and excerpt are empty.","data":{"status":400}}
  </code></pre>
  
  <p>My curl command is </p>
  
  <pre><code>curl -X POST --user admin:secret http://mysite.local/wp-json/wp/v2/posts/ -d '{"post_title":"My New Title","Content":"the stuff","excerpt":"something"}'
  </code></pre>
  
  <p>I know I must be missing something basic here.  It acts like no post data is reaching it.  Any ideas?</p>