Add basic documentation to README

[PragTob]

👋

The README is rather... empty. :) Of course you can go to the trailblazer README and eventually find the main documentation but at least a basic usage example like the trailblazer README (preferably more) and a link to the online docs would be nice - so that people who want to use it independently from trailblazer have all the chances.

Thanks and thanks for all your work,
Tobi

[johannesluedke]

Also there is no docu how to execute the tests locally

[panSarin]

New documentation about 2.1 and its Operations is there: https://2019.trailblazer.to/2.1/docs/operation.html

We will gather feedback and update README in repo. Also if you would be so kind to propose some PR with some changes in README that you think would be usefull - it would be cool!

Also: join us on zulipchat so we can discuss all ideas/problems and gather more feedback from you! https://trailblazer.zulipchat.com/join/od4yhihn6tra3ix39u4gks72/