swcarpentry/bc — pull request #244 by BillMills (2014-01-20 00:30:44+00:00)
Title: Contribution to git into lesson for SWC teacher training

This PR expands the into lesson on git backups to include an introduction to the working tree, the index, and a simple revision chain, in order to discuss more completely `git reset` and its options `--soft`, `--mixed`, and `--hard`