Improve "Getting started" guide

[Coolknight]

Hi, first of all thanks for all the time you spend on improving this project.

CONTEXT:
I have followed the "Getting Started" guide and after launching the app for develop and enter localhost:3000 I get the following error:

couldn't start a new transaction: could not create new transaction: pq: role "postgres" does not exist

Seems that I need to configure the database in order for it to work.

MY PROPOSAL:
Change the Getting started guide to either launch a docker image for the database or creating the project without the need of a database. Both will improve significantly the user experience when facing this project.

Thanks

[code1x1]

i created an issue with a detailed explanation of the problem #579