content: Add thoughts about markdown file management

This is from the works of
[firecracker](https://github.com/firecracker-microvm/firecracker/), by
analyzing how they manage markdown files.

Signed-off-by: Ruoqing He <heruoqing@iscas.ac.cn>

Author: RuoqingHe

src/repo-management/firecracker/markdown.md

@@ -0,0 +1,18 @@
+# How Firecracker Manager Their Markdown Files
+
+[Firecracker](https://github.com/firecracker-microvm/firecracker/) use
+`mdformat` (a python written program) to lint their files end with `.md`.
+
+This rule is applied by executing the `pre-commit` shell script, and enforced in
+their CI.
+
+## pre-commit Script
+
+This script lints every staged file, as of `.md`s, it simply do `mdformat
+<file-name>`. The command directly formats that file instead of produce
+differences before/after format.
+
+It is a good idea to format these files, but I don't prefer doing it without
+`--check` flag. I think it would be better to tell developers that some `.md`
+files are not in a preferred form that `mdformat` thinks, instead of changing it
+directly and developers may well get confuse on what is going to be committed.