This is a guide to root Panasonic T31
First of all, download and install framaroot.apk (just search it on google)
Open framaroot and in "Select an action to execute after root" choose install supersu.
Then in "Select an exploit in the list above to potentially root your device", select Barahir.
When it show success, reboot your phone and now you are rooted
Rooting will void your warranty so, you can always unroot too using framaroot
Please hit thanks if it helped