Add reverse-string to ruby exercises

[jbergenson]

Add reverse-string exercise to ruby/exercises.

[emcoding]

Hi @Bergbergs! GitHub says it's your first PR here. Well, congrats. It looks good.

You may have noticed that we're currently restructuring the track and that's why we're really picky about the exercises.

So, @exercism/ruby, what do you think?

• Pro: it's an easy exercise, and we currently have not many for people to play with after Hello World (while waiting for mentoring on TwoFer).
• Cons:
  • it's too easy to my liking; String#reverse is in every tutorial, even easier than Resistor Color, which we added to fill the gap that removing Flatten Array left.
  • similar to Flatten Array, it's tempting to ask students to implement the method themselves. That's really not what the track/mentoring should start with (and the main reason to move Flatten Array . 1) Because it sets the wrong tone imo. 2) Because it will make it hard(er) for me to monitor the effect of recent changes to the start of the track.

I tend to vote not to implement it, but I'm open to other opinions.
(However, I may ask to wait 2 weeks, so that I have time to gather some data first.)

@bergbergs I'm requesting changes, but it's really because of the question: to implement or not to implement.

[jbergenson]

Thanks for pointing me to the documentation on restructuring. Hadn't seen that doc previously. I'll review it and keep my eye on the discussion in the meantime.

[emcoding]

And some remarks on the code.

[emcoding]

@bergbergs I'm sorry, but as nobody voted to add this, I'm not going to merge. I sincerely hope that you will keep contributing, and I'm glad you took on Transpose. :-)

@pgaspar, @kotp Shouldn't we start to document which changes/exercises have been considered or dicussed previously? So that (new) contributors can see if exercises are rejected as possible candidates, and not put in the work. If only I could think of a good way to do that....

[kotp]

Shouldn't we start to document which changes/exercises have been considered or dicussed previously? So that (new) contributors can see if exercises are rejected as possible candidates, and not put in the work. If only I could think of a good way to do that...

We could have a ".rejected_exercises" file, that we can list.

[kotp]

Though, before implementing exercises as a pull request, there should probably be an issue created. Where we can verify the points that it teaches, etc., then we can approve the addition, or reject the addition. It may still get to the PR stage, but at least we can tag the issue as "Won't Implement" by tag, and the PR as well.

[emcoding]

I created issue #983 to discuss how to document the rejected exercises.