add

doc/bugs/GIT_DIR_support_incomplete.mdwn

@@ -0,0 +1,15 @@
+`GIT_DIR` support isn't right. Git does not look for `GIT_DIR/.git`;
+git-annex does.
+
+Also, to support this scenario, support for core.worktree needs to be added
+as well:
+
+	mkdir repo workdir
+	git --work-tree=$PWD/workdir --git-dir=$PWD/repo init
+	export GIT_DIR=$PWD/repo
+	git status
+	# ok
+	git annex init "new repo"
+	# fail
+
+--[[Joey]]