Differentiate between dev and prod

tharanor_letter.py

@@ -160,5 +160,5 @@ if __name__ == '__main__':
     parser.add_argument('-p', '--port', default='5000', help="Port to bind to (default: 5000)")
     args = parser.parse_args()
     print("Falls diese Umgebung produktiv ist, nutze besser:\n"
-         f"gunicorn --bind {args.address}:{args.port} --log-level tharanor-letter.py:app")
+          f"gunicorn --bind {args.address}:{args.port} --log-level info tharanor_letter:app")
     app.run(debug=True, host=args.address, port=args.port)