Add complete financial fraud detection database with Docker, schema, data generation, and SQL exercises

- Docker setup with PostgreSQL 16 and DB-UI web interface
- Comprehensive 20+ table schema with fraud detection patterns
- Idempotent shell scripts for data generation (no Python dependency)
- Realistic geographic data (100 US cities, 210 world cities)
- 5M+ transactions with embedded fraud patterns (velocity, geographic, structuring, etc.)
- Progressive SQL exercises from beginner to advanced fraud detection
- Complete documentation and quick start guide
- Setup and verification scripts

docker/init/00-init-database.sql

@@ -0,0 +1,22 @@
+-- ============================================================================
+-- Database Initialization Script
+-- ============================================================================
+-- This script ensures the database is created and ready
+-- It runs automatically when the PostgreSQL container starts
+-- ============================================================================
+
+-- Ensure the database exists (this runs in the default postgres database)
+SELECT 'Database initialization starting...' AS status;
+
+-- Set timezone
+SET timezone = 'UTC';
+
+-- Show current database
+SELECT current_database() AS current_db, current_user AS current_user, version() AS pg_version;
+
+-- Enable required extensions
+CREATE EXTENSION IF NOT EXISTS "uuid-ossp";
+CREATE EXTENSION IF NOT EXISTS "pgcrypto";
+
+SELECT 'Extensions enabled successfully' AS status;
+