[Request] Domain manipulation

Is there any useful way to manipulate domains?

Reasoning:
let's say I have `https://s3.amazonaws.com`
I need to build endpoint with bucket name
`f.domain.add('my-bucket')`

then I need to create website out of it:
```
>> f.url
https://my-bucket.s3.amazonaws.com
>>> f.domain.part[1] = "s3-website-region"
```

In total:

```
>>> f.url
https://my-bucket.s3-website-region.amazonaws.com
```