chore: Fix readme example

README.md

@@ -52,7 +52,24 @@ that has the signature explained in sections down below.
 
 ### Usage Example (🤸 Gymnasium)
 The example loop for running the game looks like this
-```python:examples/gymnasium_example.py
+```python
+import gymnasium as gym
+
+from generals.agents import RandomAgent, ExpanderAgent
+
+# Initialize agents
+agent = RandomAgent()
+npc = ExpanderAgent()
+
+# Create environment
+env = gym.make("gym-generals-v0", agent=agent, npc=npc, render_mode="human")
+
+observation, info = env.reset()
+terminated = truncated = False
+while not (terminated or truncated):
+    action = agent.act(observation)
+    observation, reward, terminated, truncated, info = env.step(action)
+    env.render()
 ```
 
 > [!TIP]