Create ns.pp

It allows to insert NS records into db zone files
I know I'm being a stickler here, but the example source code on the readme should be consistent with other code on the readme as well as the official puppet style guide. Make it look like this
  
````
dns::record::ns { 'example.com.':
  zone => 'example.com',
  data => "$hostname.example.com.";  
}
````