Exercise 10 and 11 are missing a README.md

[psaeuerl]

I´m currently going through the self paced workshop and i am stuck on what to do at Exercises 10 and 11 on optimistic concurrency as they missing README.md files.
Some tests are red, some are green and i could not find what is expected of me to do here.

I was able to achieve the learning goals by comapring the solved and the exercise folder, but would not be able to solve this without readme.md explaining what is expected and what the etag should be.