Are redeemScripts private? When I do createmultisig in bitcoin core, I get the redeemscript as output. I of course want to save this information, but can I put this in my regular database or do I need to take extra precaution with the redeemScript? 

In Short: Should I treat the redeem script as a private key, public key, or address hash (what level of security/and do i need to treat it with). This is from a "if it get stolen" perspective. What is the worst thing someone can do with a redeemScript?
You can treat the redeemScript as the public key. The redeemScript, like the public key, is revealed entirely when you spend from your multisig address. So it will become public information, much like your public key will also become public information when it is used in an input.

The redeemScript cannot really be used to do anything particularly bad unless the redeemScript has certain conditions which allows someone to do so. For multisig, there are no such conditions. Having the redeemScript only allows you to see what the specific conditions for spending an output are, and that information by itself is not useful.