Add prometheus config, notes.

Co-authored-by: Deirdre Connolly <deirdre@zfnd.org>

README.md

@@ -20,3 +20,18 @@ Zebra is distributed under the terms of both the MIT license
 and the Apache License (Version 2.0).
 
 See [LICENSE-APACHE](LICENSE-APACHE) and [LICENSE-MIT](LICENSE-MIT).
+
+## Metrics
+
+Notes on local metrics collection:
+
+```
+# create a storage volume for grafana (once)
+sudo docker volume create grafana-storage
+
+# run prometheus with the included config
+sudo docker run --network host -v /path/to/zebra/prometheus.yaml:/etc/prometheus/prometheus.yml  prom/prometheus
+
+# run grafana
+sudo docker run -d --network host -v grafana-storage:/var/lib/grafana grafana/grafana
+```

prometheus.yaml

@@ -0,0 +1,7 @@
+scrape_configs:
+  - job_name: 'zebrad'
+    scrape_interval: 1s
+    metrics_path: '/'
+    static_configs:
+      - targets: ['localhost:9999']
+