Gets rid of the log error for ingresses.extensions

though I first interpreted the error as the SA not being found

level=error ts=2017-11-06T09:37:54.446320099Z caller=main.go:211 component=k8s_client_runtime err="github.com/prometheus/prometheus/discovery/kubernetes/kubernetes.go:245:
Failed to list *v1beta1.Ingress: ingresses.extensions is forbidden: User \"system:serviceaccount:monitoring:prometheus-custom\"
cannot list ingresses.extensions at the cluster scope: Unknown user \"system:serviceaccount:monitoring:prometheus-custom\""

Author: solsson

custom-prometheus/rbac.yaml

@@ -25,6 +25,10 @@ rules:
   resources:
   - configmaps
   verbs: ["get"]
+- apiGroups: ["extensions"]
+  resources:
+  - ingresses
+  verbs: ["get", "list", "watch"]
 - nonResourceURLs: ["/metrics"]
   verbs: ["get"]
 ---