public function create($user, $repo, $ref, $sha)
	{
		// Build the request path.
		$path = '/repos/' . $user . '/' . $repo . '/git/refs';

		// Build the request data.
		$data = json_encode(
			array(
				'ref' => $ref,
				'sha' => $sha,
			)
		);

		// Send the request.
		return $this->processResponse($this->client->post($this->fetchUrl($path), $data), 201);
	}