doUpload = function () {
		var blobService = azure.createBlobService();
		var container = field.options.containerFormatter(item, file.name);

		blobService.createContainerIfNotExists(container, { publicAccessLevel: 'blob' }, function (err) {

			if (err) return callback(err);

			blobService.createBlockBlobFromLocalFile(container, field.options.filenameFormatter(item, file.name), file.path, function (err, blob, res) {

				if (err) return callback(err);

				var fileData = {
					filename: blob.blob,
					size: file.size,
					filetype: filetype,
					etag: blob.etag,
					container: container,
					url: 'http://' + field.azurefileconfig.account + '.blob.core.windows.net/' + container + '/' + blob.blob,
				};

				if (update) {
					item.set(field.path, fileData);
				}

				callback(null, fileData);

			});
		});
	}
Uploads the file for this field