Added example configurion

config.example.php

@@ -0,0 +1,13 @@
+<?php
+$config = [
+	'app_demo_metric1' => [ // Key is being used a prometheus key
+		'help' => 'Help text for metric',
+		'command' => 'The command to be run',
+		'jsonelem' => '0.metric', // The json element where the metric is found (Dot notated)
+	],
+	'app_demo_metric2' => [ 
+		'help' => 'Help text for metric',
+		'httpurl' => 'http://example.com', // The url to get collected for the metric
+		'jsonelem' => '0.metric',
+	],
+];