Cloud9 IO disabling keybindings or Cloud9 alternative

I have found Cloud9.io and I'm going to use it for teaching people to code in html, css, javascript and php, but there is one problem. We all are czechs and if we want to create `{`, we press `Right-Alt` + `B` and for `}`, we press `Right-Alt` + `N`. However, that's a problem in Cloud9.io, whenever we press `}`, it thinks that we want to create new file, because we press `Rigth-Alt` + `N`. So is there any way to disable these keybindings, or edit their JS so it won't use any keybindings? Or if it's not possible, do you know any alternative for Cloud9.io, that I can use for teaching other people to code, so they can see my coding live, it has a chat and they can also edit their files which I can see. Thank you.