review storage hook git part

DOCUMENTATION.md

@@ -578,14 +578,30 @@ authentication over HTTP.
 This tutorial describes how to keep track of all changes to calendars and
 address books with **git** (or any other version control system).
 
-The repository must be initialized by running `git init` in the file
-system folder. Internal files of Radicale can be excluded by creating the
-file `.gitignore` with the following content:
+The repository must be initialized in the collection base directory
+of the user running `radicale` daemon.
 
-```gitignore
+```bash
+## assuming "radicale" user is starting "radicale" service
+# change to user "radicale"
+su -l -s /bin/bash radicale
+
+# change to collection base directory, assumed /var/lib/radicale/collections
+cd /var/lib/radicale/collections
+
+# initialize git repository
+git init
+
+# set user and e-mail, here minimum example
+git config user.name "$USER"
+git config user.email "$USER@$HOSTNAME"
+
+# define ignore of cache/lock/tmp files
+cat <<'END' >.gitignore
 .Radicale.cache
 .Radicale.lock
 .Radicale.tmp-*
+END
 ```
 
 The configuration option `hook` in the `storage` section must be set to
@@ -598,16 +614,16 @@ git add -A && (git diff --cached --quiet || git commit -m "Changes by \"%(user)s
 The command gets executed after every change to the storage and commits
 the changes into the **git** repository.
 
-For the hook to not cause errors either **git** user details need to be set and match the owner of the collections directory or the repository needs to be marked as safe.
-
-When using the systemd unit file from the [Running as a service](#running-as-a-service) section this **cannot** be done via a `.gitconfig` file in the users home directory, as Radicale won't have read permissions!
+Log of `git` can be investigated using
 
-In `/var/lib/radicale/collections/.git` run:
 ```bash
-git config user.name "radicale"
-git config user.email "[email protected]"
+su -l -s /bin/bash radicale
+cd /var/lib/radicale/collections
+git log
 ```
 
+In case of error messages in log, check SELinux status and related audit log and file/directory permissions.
+
 ## Documentation
 
 ### Configuration