Re: [PATCH 0/3] [doc] Remove gittutorial-2

I'm not planning to replace gittutorial-2 since the material in it
is already covered by gitdatamodel and gitcore-tutorial.
Let me know if you disagree!

I realized it might be useful to summarize the content of
gittutorial-2 to give some context for this. It introduces these
commands and files as a way to learn Git's object model:

	git cat-file
        git ls-tree
	git ls-files --stage
	.git/objects
	.git/refs/head/*
	.git/HEAD

gitdatamodel explains the Git object model in a different way,
and gitcore-tutorial introduces these same commands in
more detail.