Homemade Laundry Detergent

So today, upon a friend telling me how much money she saves, I am looking for a good homemade laundry detergent recipe. She found hers on Pinterest and it uses Fels Naptha soap. And she says it's fine for HE machines. Our washer recently had major problems to the point that it was cheaper for our warranty to replace our machine than fix it since they no longer made it we got to pick between a non HE (lile we had) and an HE so we got the HE. I really don't want to ruin it, and I want something gentle that we can use on our cloth diapers and baby clothes but that also cleans great. So I think if I can find all the ingredients I will go for it.