(feat) Add custom 'key' and 'meta' fields for 'values'

Some time I need to custom my "values" value able such as 
```
[
{username: "user1", fullname: "my name"}
]
```

and I don't want to convert it to "key", "meta".

So I create this pull request with 2 option when create a "sew": "key" and "meta" values.