add discount page

src/model/discount.ts

@@ -0,0 +1,17 @@
+export interface Discount {
+    id?: number
+    code?: string
+    title?: string
+    description?: string
+    start_at?: string
+    end_at?: string
+    type?: number
+    discount_percent?: number
+    discount_price?: number
+    is_active?: boolean
+    use_only?: number
+    use_count?: number
+    created_at?: string
+    updated_at?: string
+    deleted_at?: string
+}