Fixed variable name for vector store

app.py

@@ -38,7 +38,7 @@ cached_embedder = CacheBackedEmbeddings.from_bytes_store(embedding_model, store,
 
 vector_file = "local_vector"
 
-if not os.path.exists(imdb_csv_file):
+if not os.path.exists(vector_file):
     vector_store = FAISS.from_documents(chunked_documents, cached_embedder)
     vector_store.save_local(vector_file)
 else: