Added usage docs

doc/Extensions/InfluxDB.md

@@ -0,0 +1,35 @@
+# Enabling support for InfluxDB.
+
+Before we get started it is important that you know and understand that InfluxDB support is currently alpha at best. 
+All it provides is the sending of data to a InfluxDB install. Due to the current changes that are constantly being 
+made to InfluxDB itself then we cannot guarantee that your data will be ok so enabling this support is at your own 
+risk!
+
+### Requirements
+ - InfluxDB 0.94
+ - Grafana
+
+The setup of the above is completely out of scope here and we aren't really able to provide any help with this side 
+of things.
+
+### What you don't get
+ - Pretty graphs, this is why at present you need Grafana. You need to build your own graphs within Grafana.
+ - Support for InfluxDB or Grafana, we would highly recommend that you have some level of experience with these.
+
+RRD will continue to function as normal so LibreNMS itself should continue to function as normal.
+
+### Configuration
+```php
+$config['influxdb']['enable'] = true;
+$config['influxdb']['transport'] = 'http';
+$config['influxdb']['host'] = '127.0.0.1';
+$config['influxdb']['port'] = '8086';
+$config['influxdb']['db'] = 'librenms';
+$config['influxdb']['username'] = 'admin';
+$config['influxdb']['password'] = 'admin';
+```
+
+UDP is a supported transport and no credentials are needed if you don't use InfluxDB authentication.
+
+The same data then stored within rrd will be sent to InfluxDB and recorded. You can then create graphs within Grafana 
+to display the information you need.