Add helper script to rename assets

slides/rename.sh

@@ -0,0 +1,11 @@
+#!/bin/sh
+if ! [ -f "$1" ]; then
+  echo "File $1 not found, aborting."
+  exit 1
+fi
+if [ -f "$2" ]; then
+  echo "File $2 already exists, aborting."
+  exit 1
+fi
+git mv "$1" "$2"
+sed -i "" "s,$1,$2," */*.md