explicitly stated the save file name.

metrics_tracker = EduBotMetrics(save_file="edu_metrics.json")

app.py

@@ -23,7 +23,7 @@ client = InferenceClient(
     api_key=hf_token,
 )
 
-metrics_tracker = EduBotMetrics()
+metrics_tracker = EduBotMetrics(save_file="edu_metrics.json")
 
 math_template = ChatPromptTemplate.from_messages([
     ("system", """{system_message}