Implement database connection and error handling and also add database migrations for Event and UserPreference models

Author: Jetlum

database/database.go

@@ -1,18 +1,27 @@
 package database
 
 import (
+	"fmt"
+
+	"github.com/Jetlum/WalletAlertService/models"
 	"gorm.io/driver/postgres"
 	"gorm.io/gorm"
 )
 
-// Exported DB variable
 var DB *gorm.DB
 
 func InitDB(dsn string) error {
 	var err error
 	DB, err = gorm.Open(postgres.Open(dsn), &gorm.Config{})
 	if err != nil {
-		return err
+		return fmt.Errorf("failed to connect to database: %w", err)
 	}
+
+	// Run migrations
+	err = DB.AutoMigrate(&models.Event{}, &models.UserPreference{})
+	if err != nil {
+		return fmt.Errorf("failed to run migrations: %w", err)
+	}
+
 	return nil
 }