Update tfkit.mk

tfkit.mk

 #
 # Adds targets: test to run tfkit tests, tfkit to deploy tfkit, tfkit_update to
 # pull tfkit updates, and tfkit_delete to remove the tfkit code.
+#
+# NOTE: Do not edit this file in your project directory as it will overwrite
+#       itself when you call tfkit_update!!!
 
 
 test: tfkit
 
 tfkit_update: tfkit
 	@cd tfkit
-	@git --git-dir tfkit/.git pull
+	@git -C tfkit pull
+	@cp tfkit/tfkit.mk .
 
 .PHONY: test