feat: add order and order_item models

backend/models/order.go

@@ -0,0 +1,25 @@
+package models
+
+import (
+	"time"
+)
+
+type Order struct {
+	ID              uint      `json:"id" gorm:"primaryKey"`
+	UserID          uint      `json:"user_id" gorm:"not null;index"`
+	Status          string    `json:"status" gorm:"not null"`
+	DeliveryAddress string    `json:"delivery_address" gorm:"not null"`
+	TotalPrice      float64   `json:"total_price" gorm:"not null"`
+	CreatedAt       time.Time `json:"created_at"`
+	UpdatedAt       time.Time `json:"updated_at"`
+	Items           []OrderItem
+}
+
+type OrderItem struct {
+	ID       uint    `json:"id" gorm:"primaryKey"`
+	OrderID  uint    `json:"order_id" gorm:"not null;index"`
+	ItemID   uint    `json:"item_id" gorm:"not null;index"`
+	Quantity float64 `json:"quantity" gorm:"not null"`
+	Price    float64 `json:"price" gorm:"not null"`
+	Item     Item    `json:"item" gorm:"foreignKey:ItemID"`
+}