Update Readme.
Update Readme.

Add a note about how to connect to the dashboard.

Change-Id: Ief46a0602befea90b5f5cf8d10020009bd11a426

stackforge/fuel-plugin-influxdb-grafana,stackforge/fuel-plugin-influxdb-grafana,stackforge/fuel-plugin-influxdb-grafana,stackforge/fuel-plugin-influxdb-grafana