Vroot no longer works with latest firmware.... but this does....
Find all you need here. Zip file with all required tools. 70. Mb file. Took all day to find this. Eventually found it on a russian site.
Worked perfect for me. it didn't wipe my user data. Or apps. Instructions included in README file.. Before using this, You will need to uninstall any existing yoga drivers from your PC first
Basically this does a temp recovery rom reboots into it and you flash the supersu
Copy n paste link below for files... xda didn't allow me to post with a proper hyperlink as I'm a new user still