function star( slug, opts, clbk ) {
	factory( opts, clbk )( slug );
}
Stars a repository.

@param {string} slug - repository slug
@param {Object} opts - function options
@param {string} opts.token - GitHub access token
@param {string} [opts.useragent] - user agent string
@param {Function} clbk - callback to invoke upon query completion
@returns {void}