fix: Add slug column to parties table and update seed data

- Added slug column to parties table via migration
- Updated seed data to properly assign slug values to Party records
- Fixed NoMethodError when assigning slug attribute in seed file

This resolves the ActiveModel::UnknownAttributeError that occurred
when trying to set the slug attribute on Party model instances.

config/database.yml

@@ -26,7 +26,8 @@ development:
 # re-generated from your development database when you run "rake".
 # Do not set this db to the same as development or production.
 test:
-  database: aperonight_development
+  <<: *default
+  database: aperonight_test
   # adapter: sqlite3
   # pool: <%= ENV.fetch("RAILS_MAX_THREADS") { 5 } %>
   # database: data/test.sqlite3