Hammurabi was a very influential person and we still use sayings that he said, yet he was never put into the bible(not that I have seen). Why would he not be put into "God's book" when many of his time considered him an envoy of gods? Is it possible that his stories were lost to Christians?
The Bible's Old Testament is not an originally Christian text; rather, it is derived from the Jewish Tanakh. The text explicitly just contains stories of the forerunners, kings, and prophets of the Jewish/Israelite people. Hammurabi was a fellow with a starkly different faith from an enemy region who lived several hundred years before most of the other people. He was influential, yes, but entirely unrelated to the religious, cultural, and political traditions of the Old Testament.
Eh, Christians didn't write the Bible. Well, the Old Testament. Why would Israelites put in Hammurabi's story (who was born in the 19th century BCE) if he has nothing to do with their origins?