Added Backend

backend/db/schema/serialexecutions.ts

@@ -0,0 +1,21 @@
+import {
+    pgTable,
+    bigint,
+    timestamp,
+    text,
+    jsonb,
+    boolean,
+    uuid,
+} from "drizzle-orm/pg-core"
+import {tenants} from "./tenants";
+
+export const serialExecutions = pgTable("serial_executions", {
+    id: uuid("id").primaryKey().defaultRandom(),
+    tenant: bigint("tenant", { mode: "number" })
+        .notNull()
+        .references(() => tenants.id),    executionDate: timestamp("execution_date").notNull(),
+    status: text("status").default("draft"), // 'draft', 'completed'
+    createdBy: text("created_by"), // oder UUID, je nach Auth-System
+    createdAt: timestamp("created_at").defaultNow(),
+    summary: text("summary"), // z.B. "25 Rechnungen erstellt"
+});