Add Gym-Trading-Env to Thrid Party Environments (#487)

docs/environments/third_party_environments.md

@@ -59,6 +59,13 @@ gym-jiminy presents an extension of the initial Gym for robotics using [Jiminy](
 
 Highly scalable and customizable Safe Reinforcement Learning library.
 
+### [gym-trading-env: Trading Environment](https://gym-trading-env.readthedocs.io/)
+
+[![Gymnasium version dependency](https://img.shields.io/badge/Gymnasium-v0.28.1-blue)]()
+[![Github stars](https://img.shields.io/github/stars/ClementPerroud/Gym-Trading-Env)]()
+
+Gym Trading Env simulates stock (or crypto) market from historical data. It was designed to be fast and easily customizable.
+
 ### [stable-retro: Classic retro games, a maintained version of OpenAI Retro](https://github.com/MatPoliquin/stable-retro)
 
 [![Gymnasium version dependency](https://img.shields.io/badge/Gymnasium-v0.27.1-blue)]()