Remove Serbian colors including Braon from database

- Remove Serbian color entries from schema.sql
- Add migration to delete Serbian colors from existing databases
- Add migration runner scripts for easier database updates
- Install pg package for PostgreSQL client support

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: DaX <noreply@anthropic.com>

database/migrations/005_remove_serbian_colors.sql

@@ -0,0 +1,2 @@
+-- Migration to remove Serbian colors from boje table
+DELETE FROM boje WHERE name IN ('Bela', 'Crna', 'Crvena', 'Plava', 'Zelena', 'Žuta', 'Narandžasta', 'Ljubičasta', 'Siva', 'Braon');