Lesson 3: Add description for force delete in Solutions

[krishnanj]

In [lesson-3/ Creating a Repository] of Version Control with Git there is a solution at the end which describes how to remove the .git folder in the moons subdirectory.

Here the idea of recursive force deletion of folders is motivated using the command rm -rf moons/.git. However, from my skimming, there is no description of what is force delete or why we should use it here, only a warning to use it carefully. I think it is useful to have a longer description in the solutions section. If this issue is approved, I can submit a PR for the same.

On a similar note, I also noticed that there isn't a focus on removing files and directories with git [correct me if I am wrong]. Perhaps its good to integrate a short description on git rm commands in one of the tutorials?

[nhejazi]

Thanks for bringing this up; I think this is a good point. In my teaching experience, usually the Git lesson is taught after a lesson that introduces shell commands, so this lack of explanation of rm -rf is possibly an artifact of relying on teaching in that order. I do think it's worth adding a short description of rm -rf as done in #560 so that the inherent danger in possibly abusing this command is less nebulous.

On another note, this is a fairly introductory lesson and I think git rm and related commands might be out of scope for this level of introduction. It would be nice to see a lesson covering some of these concepts but it might fall in an appendix section of the lesson or under advanced topics.

[nhejazi]

Resolved by #560.