function getRefreshToken(refreshToken) {
 // imaginary DB queries
 db.queryRefreshToken({refresh_token: refreshToken})
 .then(function(token) {
 return Promise.all([
 token,
 db.queryClient({id: token.client_id}),
 db.queryUser({id: token.user_id})
 ]);
 })
 .spread(function(token, client, user) {
 return {
 refreshToken: token.refresh_token,
 refreshTokenExpiresAt: token.expires_at,
 scope: token.scope,
 client: client, // with 'id' property
 user: user
 };
 });
}