Update app.py

app.py

@@ -21,7 +21,7 @@ DEFAULT_API_URL = "https://agents-course-unit4-scoring.hf.space"
 class GeminiFlashModel:
     def __init__(self, model_id="gemini-1.5-flash", api_key=None):
         import google.generativeai as genai
-        genai.configure(api_key=api_key or os.getenv("GOOGLE_API_KEY"))
+        genai.configure(api_key=api_key or os.getenv("GEMINI_API_KEY"))
         self.model = genai.GenerativeModel(model_id)
         self.system_prompt = SYSTEM_PROMPT