Add information that user.name should be set to actual name

[AnnikaLau]

Users want to set user.name to their GitHub name. We should explain on the slides and in the exercises that they should use their actual first and last name

[AnnikaLau]

Side comment: init_repo_remote doesn't work if user.name and user.email is not set

[AnnikaLau]

Solved by 4a6f8d9