Invoice Generator

## Features

- **Customer Management**: Store customer details (name, email, address)
- **Invoice Creation**: Dynamic line items with description, quantity, and rate
- **Auto-calculations**: Subtotals, tax, and grand totals computed automatically
- **Status Tracking**: Draft → Sent → Paid → Overdue workflow
- **Mark as Paid**: Record payment dates with one click
- **Print-Ready**: CSS print styles for professional PDF output
- **Company Branding**: Logo placeholder for customization

## Database

Powered by PostgreSQL with proper relational structure:
- Customers table
- Invoices with status and dates
- Invoice line items for flexible billing

## Use Cases

- Freelancers tracking client payments
- Small businesses sending invoices
- Consultants managing billing
- Anyone needing simple invoicing