Update doc

Readme.md

@@ -7,6 +7,7 @@ Duplicity based backup for ftp servers
 
 ```sh
 apt-get installl duplicity lftp
+cd /opt
 git clone https://gitlab.tetras-libre.fr/nocloud/duplicity-ftp-backup
 cp .env.sample .env
 ```
@@ -16,5 +17,5 @@ Adapt `.env`
 Then add a cronjob like
 
 ```
-0 1 * * 1,3,5,7 /root/duplicity-ftp-backup/backup.sh > /var/log/bckp.log 2>&1
+0 1 * * 1,3,5,7 /opt/duplicity-ftp-backup/backup.sh > /var/log/bckp.log 2>&1
 ```