Mentioning prefixes

docs/dev/intro.md

@@ -9,12 +9,57 @@ the users, but for people who want to work on PyPDF2 itself.
 pip install -r requirements/dev.txt
 ```
 
-## Runnin Tests
+## Running Tests
 
 ```
 pytest .
 ```
 
+## Tools: git and pre-commit
+
+Git is a command line application for version control. If you don't know it,
+you can [play ohmygit](https://ohmygit.org/) to learn it.
+
+Github is the service where the PyPDF2 project is hosted. While git is free and
+open source, Github is a paid service by Microsoft - but for free in lot of
+cases.
+
+[pre-commit](https://pypi.org/project/pre-commit/) is a command line application
+that uses git hooks to automatically execute code. This allows you to avoid
+style issues and other code quality issues. After you entered `pre-commit install`
+once in your local copy of PyPDF2, it will automatically be executed when
+you `git commit`.
+
+## Commit Messages
+
+Having a clean commit message helps people to quickly understand what the commit
+was about, witout actually looking at the changes. The first line of the
+commit message is used to [auto-generate the CHANGELOG](https://github.com/py-pdf/PyPDF2/blob/main/make_changelog.py). For this reason, the format should be:
+
+```
+PREFIX: DESCRIPTION
+
+BODY
+```
+
+The `PREFIX` can be:
+
+* `BUG`: A bug was fixed. Likely there is one or multiple issues. Then write in
+   the `BODY`: `Closes #123` where 123 is the issue number on Github.
+   It would be absolutely amazing if you could write a regression test in those
+   cases. That is a test that would fail without the fix.
+* `ENH`: A new feature! Describe in the body what it can be used for.
+* `DEP`: A deprecation - either marking something as "this is going to be removed"
+   or actually removing it.
+* `ROB`: A robustness change. Dealing better with broken PDF files.
+* `DOC`: A documentation change.
+* `TST`: Adding / adjusting tests.
+* `DEV`: Developer experience improvements - e.g. pre-commit or setting up CI
+* `MAINT`: Quite a lot of different stuff. Performance improvements are for sure
+           the most interesting changes in here. Refactorings as well.
+* `STY`: A style change. Something that makes PyPDF2 code more consistent.
+         Typically a small change.
+
 ## Benchmarks
 
 We need to keep an eye on performance and thus we have a few benchmarks.