code: function (db, id, doc, metadata, cb) {
  			var operations = [
  				{
  					Method: "PUT",
  					Document: doc,
  					Metadata: metadata,
  					Key: id
  				}
  			];
  			request.post({
  				url: host + 'databases/' + db + '/bulk_docs',
  				headers: {
  					'Content-Type': 'application/json; charset=utf-8'
  				},
  				body: JSON.stringify(operations)
  			}, function (error, response, resBody) {
  				if (!error && response.statusCode === 200) {
  					var result = JSON.parse(resBody);
  					cb(null, result);
  				} else {
  					cb(error || new Error(response.statusCode), null);
  				}
  			});
  		}
docs: Overwrites given document with given id.
  @param {string} db
  @param {string} id
  @param {Object} doc
  @param {Object} metadata
  @param {Function} cb