add bugsnag logrus hook

Signed-off-by: Matt Tescher <matthew.tescher@docker.com>

vendor/github.com/Shopify/logrus-bugsnag/README.md

@@ -0,0 +1,24 @@
+## logrus-bugsnag
+
+[![Build Status](https://travis-ci.org/Shopify/logrus-bugsnag.svg)](https://travis-ci.org/Shopify/logrus-bugsnag)
+
+logrus-bugsnag is a hook that allows [Logrus](https://github.com/sirupsen/logrus) to interface with [Bugsnag](https://bugsnag.com).
+
+#### Usage
+
+```go
+import (
+  log "github.com/sirupsen/logrus"
+  "github.com/Shopify/logrus-bugsnag"
+  bugsnag "github.com/bugsnag/bugsnag-go"
+)
+
+func init() {
+  bugsnag.Configure(bugsnag.Configuration{
+    APIKey: apiKey,
+  })
+  hook, err := logrus_bugsnag.NewBugsnagHook()
+  logrus.StandardLogger().Hooks.Add(hook)
+}
+```
+