.then(function(data){
token = data.token;
// secondary index key
var key = "user_id:" + user_id;
redis_client.smembers(key, function(err, members){
if (err)
return done(err);
// members array should contain token
for (var i = 0; i < members.length; i++) {
if (members[i] == token)
return done();
}
done(new Error("user_id secondary index hasn't been used"));
});
}).catch(done);