docs: update readme.md

README.md

@@ -147,6 +147,14 @@ teldrive run --help
 | --tg-uploads-retention               | Uploads retention duration.Duration to keep failed uploaded chunks in db for resuming uploads.                       | No       | 360h (30 days)                                               |
 
 
+```ts
+	DebugLevel = -1
+	InfoLevel = 0
+	WarnLevel = 1
+	ErrorLevel = 2
+```
+Possible log level values
+
 **You Can also set config values through env varibles.**
 - For example ```tg-session-file``` will become ```TELDRIVE_TG_SESSION_FILE``` same for all possible flags.