feat: creates backend for the project

backend/src/routes/import.ts

@@ -0,0 +1,22 @@
+import { Router } from 'express';
+import { asyncHandler } from '../utils';
+import { importStatement, isValidationError } from '../services/import';
+
+const router = Router();
+
+router.post(
+  '/statement',
+  asyncHandler(async (req, res) => {
+    const result = await importStatement(req.body);
+    if (isValidationError(result)) {
+      res.status((result as { status: number }).status).json({
+        error: (result as { error: string }).error,
+        message: (result as { message: string }).message,
+      });
+      return;
+    }
+    res.json(result);
+  }),
+);
+
+export default router;