Update app.py

app.py

@@ -179,4 +179,5 @@ async def list_voices():
     return {"voices": voice_options}
 
 if __name__ == "__main__":
- uvicorn.run( app, host="0.0.0.0", port=8000, reload=True)
+    # Change to use import string format
+    uvicorn.run("app:app", host="0.0.0.0", port=8000, reload=True)