Not able to add a contact into google in PHP curl - php

Question

I want to add a contact with data to google contacts.i am getting error as "There was an error in your request. That's all we know."
The code is as follows
<?php
$contact_detail='<?xml version="1.0"?>
<atom:entry xmlns:atom="http://www.w3.org/2005/Atom" xmlns:gd="http://schemas.google.com/g/2005">
<gd:name>
<gd:firstName>John</gd:firstName>
<gd:additionalName> test</gd:additionalName>
<gd:givenName>Doe</gd:givenName>
</gd:name>
<gd:email address="john#doe.com" rel="http://schemas.google.com/g/2005#work"/>
<gd:email address="john2#doe.com" rel="http://schemas.google.com/g/2005#home"/>
<gd:organization rel="http://schemas.google.com/g/2005#work">
<gd:orgName>John Deere</gd:orgName>
<gd:orgTitle>Owner</gd:orgTitle>
</gd:organization>
</atom:entry>';
$url="https://www.google.com/m8/feeds/contacts/default/full";
$ch = curl_init($url);
curl_setopt($ch, CURLOPT_MUTE, 1);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: text/xml'));
curl_setopt($ch, CURLOPT_POSTFIELDS, "$contact_detail");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$output = curl_exec($ch);
print($output);
curl_close($ch);

Answer 1

https://developers.google.com/google-apps/contacts/v2/developers_guide_protocol
To publish this entry, send it to the contact-list post URL as follows. First, place your Atom element in the body of a new POST request, using the application/atom+xml content type. Then send it to the post URL. For example, to add a contact to the contact list belonging to liz#gmail.com, post the new entry to the following URL: https://www.google.com/m8/feeds/contacts/liz%40gmail.com/full