So my sister is coming to visit me at my place and isn't aware that I smoke pot, trip on shrooms etc. and I'd rather keep it that way for simplicity's sake . I wanted to get some kind of lock to put on my door just so when I'm out and about or whatever she doesn't stumble in and find my stash and then we get into some huge argument or something. I was gonna get a deadbolt but obviously that doesn't work from outside. What's a simple, cheap lock I can buy that's two-way and easy to install? thanks guys.