added logout/login after adding to dialout group

INSTALL.md

@@ -53,7 +53,8 @@ sudo chown $USER /dev/ttyUSB*
 
 - most linux systems just need to have you added to the dialout group as that's persistent and more secure.
 
-sudo usermod -aG dialout $USER
+sudo usermod -aG dialout $USER 
+(don't forget to log out and log in)
 
 
 ### opensuse install ###