feat: changed backend-pg to backend

backend/tsup.config.js

@@ -0,0 +1,13 @@
+import { defineConfig } from "tsup";
+
+export default defineConfig({
+  shims: true,
+  format: "esm",
+  loader: {
+    ".handlebars": "copy",
+    ".md": "copy"
+  },
+  external: ["../../../frontend/node_modules/next/dist/server/next-server.js"],
+  outDir: "dist",
+  entry: ["./src"]
+});