(If you're unfamiliar with how Sinatra works, we recommend[reading the Sinatra guide][Sinatra].)

Start this server up. By default, Sinatra starts on port`9393`, so you'll want

Start this server up. By default, Sinatra starts on port`4567`, so you'll want

to configure ngrok to start listening for that, too.

In order for this server to work, we'll need to set a repository up with a webhook.

The webhook should be configured to fire whenever a Pull Request is created, or merged.

Go ahead and create a repository you're comfortable playing around in. Might we

suggest[@octocat's Spoon/Knife repository](https://github.com/octocat/Spoon-Knife)?

After that, you'll create a new webhook in your repository, feeding it the URL

that ngrok gave you:

that ngrok gave you, and choosing`application/x-www-form-urlencoded` as the

content type: