Allow to run /backup.sh script as standalone

fixes #5

README.md

@@ -24,12 +24,12 @@ You can use the crontab of your host to schedule the backup and the container wi
 
 Example using the integrated Backup script. You can use Environment variables for database and backup location
 ```sh
-docker run --rm --volumes-from=bitwarden bruceforce/bw_backup /backup.sh
+docker run --rm --volumes-from=bitwarden bruceforce/bw_backup manual
 ```
 
 If you want to run the sqlite commands manually you can use the following command
 ```sh
-docker run --rm --volumes-from=bitwarden bruceforce/bw_backup sqlite3 $DB_FILE ".backup $BACKUP_FILE"
+docker run --rm --volumes-from=bitwarden --entrypoint sqlite3 bruceforce/bw_backup $DB_FILE ".backup $BACKUP_FILE"
 ```
 
 ## Environment variables

entrypoint.sh

@@ -1,9 +1,23 @@
 #!/bin/sh
+# vim: tabstop=2 shiftwidth=2 expandtab
 
 #set -ux
 
 BACKUP_CMD="/sbin/su-exec ${UID}:${GID} /app/backup.sh"
 
+# For compatibility reasons
+if [ "$1" = "/backup.sh" ]; then
+  >&2 echo "Using /backup.sh is deprecated and will be removed in future versions! Please use \`manual\` as arugment instead"
+  $BACKUP_CMD
+fi
+
+# Just run the backup script
+if [ "$1" = "manual" ]; then
+  $BACKUP_CMD
+fi
+exit 0
+
+# Initialize cron
 echo "Running as $(id)"
 if [ "$(id -u)" -eq 0 ] && [ "$(grep -c "$BACKUP_CMD" "$CRONFILE")" -eq 0 ]; then
   echo "Initalizing..."