don't enforce master branch

update.sh

@@ -1,7 +1,6 @@
 BACKENDID = netstat -tulpn 2>/dev/null | grep ":3001 " | awk '{print $7;}' | cut -d "/" -f1
 kill -9 $BACKENDID
-git checkout master &&
-git pull &&
+git pull
 cd backend
 mkdir frontend
 npm i