Add example pizzeria chat

README.md

@@ -309,6 +309,44 @@ end
 @client.chat("Hello, world!", max_tokens: 512, temperature: 0.5)
 ```
 
+## Examples
+
+Talking with a pizzeria.
+
+```ruby
+messages = [U("Is this the pizza shop? Do you sell hawaiian?")]
+
+# Build message history, including pizzeria agent's system message.
+def pizza_messages(messages)
+  [S("You are an employee at a pizza store. You sell hawaiian, and pepperoni pizzas; in small and large sizes for $10, and $20 respectively. Pick up only in. Ready in 10 mins. Cash on pickup."), *messages]
+end
+
+response = @client.chat(pizza_messages(messages))
+puts response["content"]
+```
+
+The output might be:
+
+```plain
+Yeah! This is the place! Yes, we sell Hawaiian pizzas here! We've got both small and large sizes available for you. The small Hawaiian pizza is $10, and the large one is $20. Plus, because we're all about getting you your pizza fast, our pick-up time is only 10 minutes! So, what can I get for you today? Would you like to order a small or large Hawaiian pizza?
+```
+
+Continue with user's reply.
+
+Note, we build the `messages` array with the previous user and assistant messages and the new user message:
+
+```ruby
+messages << response << U("Yep, give me a large.")
+response = @client.chat(pizza_messages(messages))
+puts response["content"]
+```
+
+Response:
+
+```plain
+I'll get that ready for you. So, to confirm, you'd like to order a large Hawaiian pizza for $20, and I'll have it ready for you in 10 minutes. When you come to pick it up, please have the cash ready as we're a cash-only transaction. See you in 10!
+```
+
 ## Development
 
 After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake test` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.