Add support for justinmimbs/date

[MartinSStewart]

I have a Date value that I'd like to format using this package. This seems like a natural thing to do since this package is called date-format but currently it seems to only support Time.Posix.

That said, there might be some design consideration if you decide to add this. For example, should phantom types be used to prevent the user from using hour, minute, second, etc with a Date value? Or should those values just default to 0?