create collection before inserting docs

app.py

@@ -32,6 +32,7 @@ class RetrievalAugmentedQAPipeline:
         self.llm = llm
         self.vector_db_retriever = vector_db_retriever
         self.vector_db_retriever.delete_collection()
+        self.vector_db_retriever.create_collection()
 
     async def arun_pipeline(self, user_query: str):
         context_data = self.vector_db_retriever.search_similar(user_query)