Baby sleeping through the night 👀

Raven
So I was at the nail shop talking to a group of random moms who gave me tip to get baby to sleep through the night. They said to breastfeed baby and once baby is done with the breast (or cut feeding short) to supplement with formula and a half a teaspoon of baby cereal. They claim this will make them sleep longer. Has anyone heard of this or has tried this technique?? Please share! 
*** Update**** 
Just to be clear I NEVER said that I was going to feed my baby cereal I was simply just asking if anyone has HEARD of this technique and if they tried it what were their results. I didn't want a bandwagons of negative ppl telling me what to do I  just wanted ppl to SHARE their negative/positive experience with this technique. Or tell me if they have even HEARD of this.