[enh] add a script for crontab

should_i_rebuild.sh

@@ -0,0 +1,24 @@
+#!/bin/bash
+
+set -ex
+
+if [ ! "$1" ]
+then
+    echo "I need a github <username>:<token> to run as first argument"
+    exit 1
+fi
+
+before_official=$(sha256sum official.json)
+before_community=$(sha256sum community.json)
+
+git pull
+
+if [ "$before_official" != "$(sha256sum official.json)" ]
+then
+    python ./list_builder.py -g $1 official.json
+fi
+
+if [ "$before_community" != "$(sha256sum community.json)" ]
+then
+    python ./list_builder.py -g $1 community.json
+fi