update README

ospabhost/backend/prisma/add_custom_storage_plan.sql

@@ -0,0 +1,18 @@
+-- Добавить колонку pricePerGb для расчёта кастомного тарифа
+ALTER TABLE storage_plan ADD COLUMN pricePerGb DECIMAL(10, 4) NULL AFTER price;
+
+-- Добавить кастомный тариф
+INSERT INTO storage_plan
+  (code, name, price, pricePerGb, quotaGb, bandwidthGb, requestLimit, `order`, isActive, description)
+VALUES
+  ('custom', 'Custom', 0, 0.5, 0, 0, 'Неограниченно', 999, TRUE, 'Кастомный тариф - укажите нужное количество GB')
+ON DUPLICATE KEY UPDATE
+  name = VALUES(name),
+  price = VALUES(price),
+  pricePerGb = VALUES(pricePerGb),
+  quotaGb = VALUES(quotaGb),
+  bandwidthGb = VALUES(bandwidthGb),
+  requestLimit = VALUES(requestLimit),
+  `order` = VALUES(`order`),
+  isActive = VALUES(isActive),
+  description = VALUES(description);