Update file README.md

README.md

@@ -42,7 +42,7 @@ pip install pygame==2.5.2
 
 ### Usage
 
-Here is an example of how to use Gym to solve the `CartPole-v1` environment:
+Here is an example of how to use Gym to solve the `CartPole-v1` environment (https://gymnasium.farama.org/environments/classic_control/cart_pole/):
 
 ```python
 import gym