He said that Christianity (not Judeo-Christianity iirc) is a slave morality. It preaches equality N. says and only a slave or an underling would preach equality and they do so because they have less than their masters. So in that way it is a self-interested morality (if you accept it was advocated by an underclass). He contrasts this with a master morality (might is right basically).
What is ethics or morality? It's what values you hold and project onto the world, correct? So I guess N. is saying that these values are subject to your socio-economic place in the world. That's quite materialist -- like Marx, who said more or less the same thing except that Marx said that the material conditions of your (as a class) existence shape your ideology. I think the text to look at for N. is "On The Genealogy of Morals" and the text for Marx is "The German Ideology".
Regarding the provenance of deconstruction. I'm not about to read "Of Grammatology" any time soon but you are the first person I've heard to assert the Heidegger should be given credit so you need to, you know, cite your source please.