Integrate with codecov

[lukasz-pyrzyk]

@pawelklimczyk Could you please visit https://codecov.io/, log in via github and integrate repo with codecov?

[pawlos]

@lukasz-pyrzyk I think I can do it too, but what we will gain with this integration?

[lukasz-pyrzyk]

I wanted to add OpenCover to generate reports about code coverage and send it to codecov, but @pawelklimczyk is working on it right now.

Except classic code coverage result and badge for github, we will see code coverage of incoming PR

[pawlos]

@lukasz-pyrzyk ok, sounds nice

[pawelklimczyk]

still stuff to do. 🎱

[pawlos]

@pawelklimczyk if you're busy I can do this (I think :])

[lukasz-pyrzyk]

@pawelklimczyk i can help you if you have any problems

[pawelklimczyk]

done.