update readme

### What is the problem / feature ?

There were some extra steps needed for the README

### How did it get fixed / implemented ?

- Added step about installing postgresql
- Added step about setting up your database.
- Added some extra formatting.

### How can someone test / see it ?

Look here https://github.com/Apogaea/voldb/blob/piper/update_readme/README.md

*Here is a cute baby animal picture for your troubles...*

![dog-goat-32](https://f.cloud.github.com/assets/824194/2430980/120f5378-ad12-11e3-819f-59a6b686d975.jpg)