Improve on #2 by Preventing Merge Commit

#2 worked well!

Now, to try to get super clean, let's merge in the feature branch to master using `--no-ff` so no merge commit is created.

- Perform the rebase on the feature branch (`git rebase -i master`)
- Force push the feature branch to GitHub (`git push origin feature/3 --force`)
- Merge with master from command line (`git checkout master`; `git merge feature/3 --no-ff`)