Add initial project structure with core functionality for book and stationery uploads

- Created main application entry point in `main.go`.
- Added configuration management in `config/config.go` and tests in `config/config_test.go`.
- Implemented handlers for book and stationery uploads in `handlers/book.go` and `handlers/stationery.go`, including validation logic.
- Established database connection and services in `services/database.go` and `services/book_service.go`.
- Defined models for books and stationery in `models/book.go` and `models/stationery.go`.
- Set up Firebase integration for image uploads in `services/firebase.go`.
- Created migration scripts for database schema in `migrations/001_create_tables.sql` and subsequent updates.
- Added CORS and error handling middleware.
- Included comprehensive tests for handlers, services, and utilities.
- Documented API endpoints and usage in `README.md` and migration instructions in `migrations/README.md`.
- Introduced `.gitignore` to exclude unnecessary files and directories.
- Added Go module support with `go.mod` and `go.sum` files.
- Implemented utility functions for slug generation and validation in `utils/slug.go` and `utils/validation.go`.

main.go

@@ -0,0 +1,87 @@
+package main
+
+import (
+	"log"
+	"os"
+	"os/signal"
+	"syscall"
+
+	"jd-book-uploader/config"
+	"jd-book-uploader/handlers"
+	"jd-book-uploader/middleware"
+	"jd-book-uploader/services"
+
+	"github.com/gofiber/fiber/v2"
+)
+
+func main() {
+	// Load configuration
+	cfg, err := config.LoadConfig()
+	if err != nil {
+		log.Fatalf("Failed to load configuration: %v", err)
+	}
+
+	// Initialize database connection
+	_, err = services.NewDBPool(cfg)
+	if err != nil {
+		log.Fatalf("Failed to connect to database: %v", err)
+	}
+	defer services.CloseDB()
+	log.Println("Database connected successfully")
+
+	// Initialize Firebase
+	_, err = services.InitFirebase(cfg)
+	if err != nil {
+		log.Fatalf("Failed to initialize Firebase: %v", err)
+	}
+	log.Println("Firebase initialized successfully")
+
+	// Create Fiber app
+	app := fiber.New(fiber.Config{
+		AppName: "JD Book Uploader API",
+	})
+
+	// Register middleware
+	app.Use(middleware.RecoverHandler()) // Recover from panics
+	app.Use(middleware.ErrorHandler)     // Global error handler
+	app.Use(middleware.SetupCORS(cfg))   // CORS
+	app.Use(middleware.SetupLogger())    // Request logging
+
+	// Register routes
+	api := app.Group("/api")
+	api.Get("/health", handlers.HealthCheck)
+	api.Post("/books", handlers.UploadBook)
+	api.Post("/stationery", handlers.UploadStationery)
+
+	// Start server
+	port := cfg.Port
+	if port == "" {
+		port = "8080"
+	}
+
+	// Graceful shutdown
+	c := make(chan os.Signal, 1)
+	signal.Notify(c, os.Interrupt, syscall.SIGTERM)
+
+	go func() {
+		log.Printf("Server starting on port %s", port)
+		if err := app.Listen(":" + port); err != nil {
+			log.Fatalf("Server failed to start: %v", err)
+		}
+	}()
+
+	<-c
+	log.Println("Gracefully shutting down...")
+
+	// Close database connection
+	if err := services.CloseDB(); err != nil {
+		log.Printf("Error closing database: %v", err)
+	}
+
+	// Shutdown Fiber app
+	if err := app.Shutdown(); err != nil {
+		log.Fatalf("Server shutdown failed: %v", err)
+	}
+
+	log.Println("Server stopped")
+}