Make it clear that Storage is a constructor

This is the standard way to declare constructors, it makes it clearer
how it's expected to be used in other places.
[docs] README updates

- Expanded examples to show adding data to the instance
- Use localhost instead of 127.0.0.1 to be more user friendly
- Added links to the schemas directory
- Other misc tweaks
Add details about hidden fields to the README

Also made some changes to the initial example so the README can be
followed step by step and the various examples will make sense and work
properly.