Provide function for copying documents

[SteffenGorenflo]

I came across a problem, where I needed to copy a whole document and only change a single value. When I consulted the couchdb wiki, I found this article https://wiki.apache.org/couchdb/HTTP_Document_API#COPY but there is no corresponding function in cradle.

The workaround I'm currently using is

var options = {
  method: 'COPY',
  path: '/' + originalDocumentID,
   headers: {
     destination: newDocumentId
    }
 };

db.query(options, function (err, data, response) {
         // handle response
});

Could it be possible to provide this function? Just a proposal, I can live with that workaround.