Update app.py

app.py

@@ -90,6 +90,7 @@ Bot Response: "In the document, 'cognitive dissonance' is defined as [definition
             self.llm,
             retriever=self.db.as_retriever(),
             memory=self.memory,
+            return_source_documents=True,
             combine_docs_chain_kwargs={"prompt": self.prompt}
         )