fix permission issue

src/streamlit_app.py

@@ -8,7 +8,10 @@ import numpy as np
 from openai import OpenAI
 
 
+os.environ['TRANSFORMERS_CACHE'] = './model_cache'
+os.environ['HF_HOME'] = './model_cache'
 
+model = SentenceTransformer('sentence-transformers/all-MiniLM-L6-v2')
 
 
 st.set_page_config(layout="wide")