Please update CONTRIBUTING.md

[romeerez]

Currently it is almost blank.
It's not clear how to run specific test, how to setup databases, etc.

I replaced all user: 'postgres' to my user because I don't have user postgres, then I tried to run specific test and got beforePG, then I added require('./__helper') to the test and currently stuck at:

TypeError: Cannot read property 'be' of undefined

For the test codes like

ArrayTest.definition.attributes[attr].type.name.should.be.equal(...)

FIxed this by adding chai dependency and

require('chai').should();

To the top of the test

P.S I think this library it great, it must live on, must be friendly to contributors

[PhilWaldmann]

Thanks for the feedback.
I'll try to update the readme and make it easier to get started in the upcoming days

The test setup is defined in the travis.yml file. But it's not designed for humans ;)