Merge pull request 'Add explanation to add-command' (#5) from Troximus/dev-tools:add into main

Reviewed-on: https://codeberg.org/mo8it/dev-tools/pulls/5

src/day_3/notes.md

@@ -12,6 +12,22 @@ The participants of the course will add a description to each of these Git subco
 
 ## git add
 
+This command stages one or more files for the next commit, adding them to everything that is committed.
+
+Examples are:
+
+```bash
+git add "example.txt"
+```
+
+or
+
+```bash
+git add --all
+```
+
+if you want to stage all changes.
+
 ## git commit
 
 ## git log