fix: install.sh: get current user instead of root on the automatic install script (#239)

* Get current user instead of root on the install.sh script

* Added automatic install steps on README.md

README.md

@@ -55,6 +55,10 @@ adb devices
 # You should now see your device
 ```
 
+### Using the automtic install script
+1. Clone this repository
+2. Run the `install.sh` as root on your terminal
+
 ## To Contribute
 
 1. Fork this repository.

install.sh

@@ -21,7 +21,7 @@ else
   groupadd adbusers
 fi
 
-usermod -a -G adbusers "$USER"
+usermod -a -G adbusers "$(logname)"
 udevadm control --reload-rules
 
 if [ "$USE_SERVICE_CMD" = "true" ]; then