models.DateTimeField(auto_now_add=True).

class AbcResource(ModelResource):

    def obj_update(self, bundle, request=None, **kwargs):
        logger.debug("Update called")
        res = super(AbcResource, self).obj_update(bundle, request)
        signals.abc_updated.send( sender=request, abc=res.obj, user=request.user )
        return res

class Abc( models.Model ):
    created = models.DateTimeField(_('created'), auto_now_add=True)

var url = root + "/api/v1/abc/" + selected_abc + "/" + "?user_key=" + user_guid + "&user_name=" + username + "&format=json";
var abc_data = xmlRequest(url, false);
abc_data["field"] = field_value;
var request = $.ajax({
                     url: url,
                     type: 'PUT',
                     contentType: 'application/json',
                     data: JSON.stringify(abc_data),
                     dataType: "application/json",
                     processData: false
                     })
request.done(function(msg) {
             console.log("Status update pass : " + msg);
             });

request.fail(function(jqXHR, textStatus) {
             console.log("Status update fail : " + jqXHR.responseText);
             console.log(jqXHR);
             });