Adding the scale email sync script to this repo. (#51)

Signed-off-by: Phil Dibowitz <phil@ipom.com>

Author: jaymzh

.github/workflows/lint.yml

@@ -17,6 +17,6 @@ jobs:
         with:
           python-version: '3.x'
       - name: Install black
-        run: pip install black
+        run: pip install black==25.12.0
       - name: Run black
         run: black --check -l 80 .

listmonk/README.md

@@ -0,0 +1,21 @@
+# Listmonk syncing script
+
+**NOTE**: This repo is currently not the live copy, but will be soon.
+
+This script keeps attendee registration data in sync with our
+listmonk instance.
+
+When people register for the event they make a choice of what email they
+want:
+
+* Logistics about this event (not optional)
+* Announcements (including future events) [optional]
+* Sponsor offers [optional]
+
+This takes that data and populates the various lists in listmonk.
+
+## A note on unsubscribes
+
+If people unsubscribe from a list, they still show up in the API as "on" that
+list, so we never have to worry about accidentally adding someone to a list
+they have unsubscribed from.