deployangel: a production verdict for every Rails deploy, in 15 minutes

CI passed, the health check is green, and your error tracker is quiet. Meanwhile a webhook route has stopped getting hits, or a nightly job never ran. No exception, so nobody hears about it. deployangel compares each release with the ones before it, route by route and job by job, and gives the deploy a verdict: Verified, Failed, or Inconclusive. The first check comes 15 minutes after the deploy. The gem sends one aggregated payload per process per minute (counts and histograms, no request bod...