Adding census_historical_migration README

backend/census_historical_migration/README.md

@@ -0,0 +1,20 @@
+# Census Historical Migration
+
+### How to run the historic data migrator:
+```
+docker compose run web python manage.py historic_data_migrator --email [email protected] \
+  --year 22 \
+  --dbkey 100010
+```
+- The email address currently must be a User in the system. As this has only been run locally so far, it would often be a test account in my local sandbox env.
+- `year` and `dbkey` are optional. The script will use default values for these if they aren't provided.
+
+### How to run the historic workbook generator:
+```
+docker compose run web python manage.py historic_workbook_generator
+  --year 22 \
+  --output <your_output_directory> \
+  --dbkey 100010
+```
+- `year` is optional and defaults to `22`.
+- The `output` directory will be created if it doesn't already exist.