Mock assignment description added

[hsl-petrhaj]

Added description of mock assignment runs based on comments of @johpiip .

[johpiip]

Hi @hsl-petrhaj! You assigned this to me. Would you like me to "take over" meaning that I should do my own commits to this branch or would you like me to review this meaning that I will give review comments if I want any changes? If you want me to review, please mark me as reviewer. 😊