Post the CI link to the PR when a CI is started

[joyeecheung]

Since human could forget to do this.

From a glance this should probably be done around

github-bot/scripts/jenkins-status.js

Lines 45 to 49 in a76688e

	pushJenkinsUpdate.pushStarted({
	owner: 'nodejs',
	repo,
	logger: req.log
	}, req.body)

[phillipj]

I'm all for automating all the things!

Think you're right about which lines to hook into.. We just gotta ensure we don't post comments about all jobs, called "checks" in GitHub UI (see below). I assume the job we should be filtering on is node-test-pull-request, right?

[joyeecheung]

I assume the job we should be filtering on is node-test-pull-request, right?

@phillipj Yes, at least we could start from there.