update README

ospabhost/backend/prisma/migrations/20251123130000_add_storage_plan/migration.sql

@@ -0,0 +1,18 @@
+-- CreateTable
+CREATE TABLE `storage_plan` (
+    `id` INTEGER NOT NULL AUTO_INCREMENT,
+    `code` VARCHAR(64) NOT NULL,
+    `name` VARCHAR(128) NOT NULL,
+    `price` DOUBLE NOT NULL,
+    `quotaGb` INTEGER NOT NULL,
+    `bandwidthGb` INTEGER NOT NULL,
+    `requestLimit` VARCHAR(64) NOT NULL,
+    `order` INTEGER NOT NULL DEFAULT 0,
+    `isActive` BOOLEAN NOT NULL DEFAULT TRUE,
+    `description` VARCHAR(191) NULL,
+    `createdAt` DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
+    `updatedAt` DATETIME(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
+
+    UNIQUE INDEX `storage_plan_code_key`(`code`),
+    PRIMARY KEY (`id`)
+) DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;