Added Configuring prometheus block

Author: ewoutp

README.md

@@ -18,6 +18,24 @@ This results in an ArangoDB Exporter exposing all statistics of
 the ArangoDB server (running at `http://<your-database-host>:8529`)
 at `http://<your-host-ip>:9101/metrics`.
 
+## Configuring Prometheus
+
+There are several ways to configure Prometheus to fetch metrics from the ArangoDB Exporter.
+
+Below you're find a sample Prometheus configuration file that can be used to fetch
+metrics from an ArangoDB exporter listening on localhost port 9101 (without TLS).
+
+```yaml
+global:
+  scrape_interval:     15s
+scrape_configs:
+- job_name: arangodb
+  static_configs:
+  - targets: ['localhost:9101']
+```
+
+For more info on configuring Prometheus go to [its configuration documentation](https://prometheus.io/docs/prometheus/latest/configuration/configuration).
+
 ## Building
 
 To build this project, you need Go 1.8 or higher and Docker installed.