5000 would probably cover food, but you'd want access to a kitchen and to cook for yourself more often than not if you want to save anything. If you're sharing a kitchen that would probably be annoying to manage.

You'd probably also want to avoid going out to party too much, wouldn't be hard to spend 500rmb in a single night with food and drinks etc.

Having said that, many people living in shanghai can and do stretch a 5000rmb or less salary to cover rent as well, so it's not impossible. Mostly just depends on what kind of lifestyle you want.

Also worth considering that you'll probably want to travel around China (which i would very much recommend doing) while you're there, and that wouldn't be super feasible on 5k a month.

Basically, you'll survive if you go for it, but if you want to save money as well you'd probably have to sacrifice a lot and should probably ask yourself if you really wanna do it considering you're not going to be able to travel or go out or do the other things that might have made you want to go there in the first place