Update readme.md

[dethos]

Currently the setup information as presented by the readme.md file seems out of date and overly complex (at least on OSX).

There should be an easier way to setup everything.

[dethos]

It should have:

• [ ] which configuration and variables are needed for each environment
• [ ] How to properly setup a production environment
• [ ] How to run tests (with and without docker)
• [ ] ...

For a more detailed information we would take into account the pains described by users (example: #249 )