Update contributing guides

Add section about slides. Add information on doing commits (inspired
from Operating Systems).

Signed-off-by: Razvan Deaconescu <[email protected]>

CONTRIBUTING.md

@@ -9,7 +9,7 @@ Some good first steps and best practices when using Git are explained here:
 
 * the Git Immersion tutorial: <https://gitimmersion.com/>
 * the Atlassian tutorial: <https://www.atlassian.com/git/tutorials/learn-git-with-bitbucket-cloud>
-* this blog post on the ROSEdu Techblog: <https://techblog.rosedu.org/git-good-practices.html>
+* this blog post on the `ROSEdu Techblog`: <https://techblog.rosedu.org/git-good-practices.html>
 
 ## Language
 
@@ -34,6 +34,19 @@ Use phrases like "find the flag", "run this command", "download the tool".
 Use [draw.io](https://app.diagrams.net/) to create diagrams.
 If using external images / diagram, make sure they use a CC BY-SA license and give credits (mention author and / or add link to the image source).
 
+## Slides
+
+Slides are to be written in Markdown, using [`reveal-md`](https://github.com/webpro/reveal-md), itself based on [`reveal-js`](https://revealjs.com/).
+Use `reveal-md` and `reveal-js` specifics to split information in slides.
+Aim to make slides attractive, sleek and simple to follow.
+
+Images and diagrams would ideally be animated on slides.
+Aim to use `reveal.js` features to animate drawing of diagrams.
+
+If `reveal.js` drawing is difficult, use [draw.io](https://app.diagrams.net/) to create diagrams.
+Ideally you would "animate" those diagrams by creating multiple incremental versions of the diagram and adding each to a slide;
+when browsing slides pieces of these diagrams will "appear" and complete the final image, rendering an animation-like effect.
+
 ## Issues
 
 When opening an issue, please clearly state the problem.
@@ -58,8 +71,47 @@ If there are multiple commits belonging to a given change, please squash the com
 
 Also make sure one pull request covers only **one** topic.
 
+### Commits
+
+Before making a commit, configure your name and email locally using:
+
+```bash
+git config --global user.name "Your Name"
+git config --global user.email "[email protected]"
+```
+
+Then make sure the email you've just configured corresponds to the one you have [set on GitHub](https://docs.github.com/en/account-and-profile/setting-up-and-managing-your-personal-account-on-github/managing-email-preferences/adding-an-email-address-to-your-github-account).
+
+After this, make your changes, `git add` them and then commit them using `git commit -s`.
+Always sign your commits using the `-s` / `--signoff` arguments to `git commit`.
+This will add the following line at the end of the commit message:
+
+```text
+Signed-off-by: Your Name <[email protected]>
+```
+
+Notice that the details above are the name and email that you configured earlier.
+
+Now the `git commit` command will open your default editor and ask you to write a commit message.
+Prefix each commit message title with the chapter it belongs to: `software-stack`, `data`, `compute`, `io`, `app-interact` and the component: `lecture` / `lab`.
+An example of a prefix is `compute/lab:`.
+Following the prefix, write a short and expressive title on the first line.
 Use commit messages with verbs at imperative mood: "Add README", "Update contents", "Introduce feature".
-Prefix each commit message with the chapter it belongs to: `software-stack`, `data`, `compute`, `io`, `app-interact`.
+
+Leave an empty line, then add a relevant description of the changes made in that commit.
+This description should include why that change is needed (fixes a bug, improves something that was inefficient, etc.).
+Wrap the lines of this description to 75 characters.
 How a good commit message should look like: <https://cbea.ms/git-commit/>
+Below is an example of a good commit message:
+
+```text
+data/lab: Fix Makefile `CFLAGS` error
+
+`CFLAGS` was incorrectly set to optimise the code to the `-O3` level. This
+caused the function `vulnerable_func()` to be inlined into the caller
+`main()`, making it impossible to overwrite `main()`'s return address with
+that of `vulnerable_func()`. This commit fixes the issue by forcing the
+compiler to not optimise the code by replacing `-O3` with `-O0` in `CFLAGS`
 
-The use of `-s` / `--signoff` when creating a commit is optional, but strongly recommended.
+Signed-off-by: Your Name <[email protected]>
+```