fix storage path

prompt_assistant.py

@@ -62,8 +62,9 @@ class Text2ImagePromptAssistant(Tool):
             )
         service_context = ServiceContext.from_defaults(llm_predictor=LLMPredictor(llm=llm))
         set_global_service_context(service_context)
-
-        self.index = load_index_from_storage(StorageContext.from_defaults(persist_dir="./storage"))  
+        
+        storage_path = os.path.join(os.path.dirname(__file__), "storage")
+        self.index = load_index_from_storage(StorageContext.from_defaults(persist_dir=storage_path))  
         self.query_engine = self.index.as_query_engine(similarity_top_k=5, text_qa_template=text_qa_template, refine_template=refine_template)
 
     def __call__(self, query_str):