updated readme

README.md

@@ -77,4 +77,10 @@ configuration is done entirely within the file `config.json`.
 - *name*: [*object*]
     - cmd: [*string*] command / path to script to execute  
     - args: [*string-array*] arguments to pass to the executed command
-    - sudo: [*boolean*] use sudo to execute the command
+    - sudo: [*boolean*] use sudo to execute the command
+
+**note:**  
+if you intend to use ninwa as a systemd-service with `sudo` make sure the configured user is allowed to execute the command without entering a password. **otherwise your service will just stop at the password prompt!**
+
+- `sudo visudo`  
+- `username ALL=(ALL) NOPASSWD: command`