docu updated

README.md

@@ -1,12 +1,29 @@
 Use BTRFS Snapshots For Backups
 ===============================
 
-Try: btrfs-snapshots.sh --help
+btrfs-snapshots.sh
+------------------
 
-Setup daily btrfs snapshot of all mounted subvols in `/etc/fstab`:
+Creates a snapshot for all btrfs volumes specified. Snapshot is named
+from the subvol name or if there is no subvol, from the path by
+appending `-snapshot-YYYY-MM-DD-HH-mm`.
+
+To create regular snapshots on a daily base, just run:
 
     sudo cp btrfs-snapshots.sh /etc/cron.daily/btrfs-snapshots
 
-If you want hourly bakups, just enter:
+If `btrfs-snapshots` is run from a `cron.daily`, `cron.hourly`,
+`cron. monthly` or `cron.weekly` directory, the periodity is
+automatically appended to the snapshot name, and the expiry is set
+meaningfull.
+
+Try: `btrfs-snapshots.sh --help`
+
+
+Installation
+------------
 
-    sudo cp btrfs-snapshots.sh /etc/cron.hourly/btrfs-snapshots
+Just call `./install.sh` to install all cron jobs. Then there will
+always be the last 24 hourly backups, the last 7 daily backups, tha
+last 4 weekly backups and all monthly backups of all your btrfs
+filesystems mounted in `/etc/fstab`.