diff --git a/vendor/google.golang.org/appengine/internal/regen.sh b/vendor/google.golang.org/appengine/internal/regen.sh
new file mode 100755
index 0000000..2fdb546
--- /dev/null
+++ b/vendor/google.golang.org/appengine/internal/regen.sh
@@ -0,0 +1,40 @@
+#!/bin/bash -e
+#
+# This script rebuilds the generated code for the protocol buffers.
+# To run this you will need protoc and goprotobuf installed;
+# see https://github.com/golang/protobuf for instructions.
+
+PKG=google.golang.org/appengine
+
+function die() {
+	echo 1>&2 $*
+	exit 1
+}
+
+# Sanity check that the right tools are accessible.
+for tool in go protoc protoc-gen-go; do
+	q=$(which $tool) || die "didn't find $tool"
+	echo 1>&2 "$tool: $q"
+done
+
+echo -n 1>&2 "finding package dir... "
+pkgdir=$(go list -f '{{.Dir}}' $PKG)
+echo 1>&2 $pkgdir
+base=$(echo $pkgdir | sed "s,/$PKG\$,,")
+echo 1>&2 "base: $base"
+cd $base
+
+# Run protoc once per package.
+for dir in $(find $PKG/internal -name '*.proto' | xargs dirname | sort | uniq); do
+	echo 1>&2 "* $dir"
+	protoc --go_out=. $dir/*.proto
+done
+
+for f in $(find $PKG/internal -name '*.pb.go'); do
+  # Remove proto.RegisterEnum calls.
+  # These cause duplicate registration panics when these packages
+  # are used on classic App Engine. proto.RegisterEnum only affects
+  # parsing the text format; we don't care about that.
+  # https://code.google.com/p/googleappengine/issues/detail?id=11670#c17
+  sed -i '/proto.RegisterEnum/d' $f
+done