Add config example to readme

example.toml

@@ -1,18 +1,23 @@
-path = "./test"
+# Specify a folder containing backups
+path = "/backups/docker"
+
+# uncomment if the backups are btrfs subvolumes
 #btrfs = true
 
 [[periods]]
-period_length = "10m"
+# For the first day, keep one backup per second (basically, don't delete backups)
+# syntax supports suffixes s, m, h, d, w
+period_length = "1d"
 chunk_size = "1s"
 
 [[periods]]
+# For the next week, keep one backup per hour
 period_length = "1w"
 chunk_size = "1h"
 
 [[periods]]
+# For the next 4 weeks, keep one backup per day
 period_length = "4w"
 chunk_size = "1d"
 
-[[periods]]
-period_length = "40w"
-chunk_size = "4w"
+# can add more [[periods]] as needed