Judaism and the Torah both developed over time. The modern versions of the Torah were probably written down in post-exilic times, beginning around 500 BCE. These would have drawn from earlier sources, both written and oral. In that sense, the community is older than the book. But the earliest oral traditions go back long before the culture was recognizably Jewish in our sense of the term; early Hebrews weren't all that different from other tribes in that area at that time. So it's probably most accurate to say that Judaism and the Torah developed together. One really couldn't exist without the other.