Change documentation of pre commit

.pre-commit-config.yaml

@@ -20,10 +20,12 @@ repos:
     hooks:
       - id: hadolint
   - repo: https://github.com/jazzband/pip-tools
+    # Makes sure the requirements.txt file is up to date
     rev: 5.2.1
     hooks:
       - id: pip-compile
   - repo: https://github.com/timothycrosley/isort
+    # Sorts import statements for you
     rev: 5.0.9
     hooks:
       - id: isort

CONTRIBUTING.md

@@ -15,8 +15,12 @@ before each commit. Use the following commands to install the hooks
 pre-commit install
 ```
 
-Running the pre-commit for the first time usually takes a little longer because `pre-commit`
-pulls some of it's hooks from upstream repositories.
+Running `git commmit` for the first time after installing the hook usually takes a
+little longer because `pre-commit` pulls it's hooks from upstream repositories.
+You can find all hooks in `.pre-commit-config.yaml`.
+
+In case you need to skip the execution of the pre-commit hooks (please don't!),
+use `git commit --no-verify`.
 
 
 ## Adding dependencies