Add a usage example

examples/random-random-walk.py

@@ -0,0 +1,29 @@
+import gym
+import numpy as np
+import gym_random_walk
+
+env = gym.make('random_walk-v0')
+
+num_episodes = 20
+num_steps_per_episode = 200
+
+collected_rewards = []
+for i in range(num_episodes):
+    s = env.reset()
+    print ("starting new episode")
+    env.render()
+    print ("started")
+    total_reward = 0
+    done = False
+    for j in range(num_steps_per_episode):
+        a = np.random.randint(env.action_space.n)
+        s1, reward, done, _ = env.step(a)
+        env.render()
+        total_reward += reward
+        s = s1
+        if done:
+            break
+    collected_rewards.append(total_reward)
+    print ("total reward ", total_reward, " after episode: ", j)
+print ("average score: ", sum(collected_rewards) / num_episodes)
+print("#########")