unable to create notification_key for gcm using node js

I am getting 404 error when I try to create notification_key in gcm using node.js. My code is

var request = require('request');

request.post({
uri: 'https://android.googleapis.com/gcm/notification',

request:
{ 
"operation": "create",
"notification_key_name": "appUser-Chris",
"notification_key": "aUniqueKey",
"registration_ids": ['**', '****']
},

headers: {
'content-type': "application/json",
'project_id' : 'fluid-booking-638',
'Authorization' : 'key=*****'
}


}, function(err, response, body) {
    console.log(err);
    console.log(response);
    console.log(body);
});

Where am I doing mistake ?

Thanks in advance.