Add Prometheus exporter link

diff --git a/doc/tools.md b/doc/tools.md
index ef916553adcf7b5dcc7150a7b99e6c3ea301dd6b..2a273e365076c3575125a223872954df531c57e8 100644 (file)
--- a/doc/tools.md
+++ b/doc/tools.md
@@ -84,3 +84,9 @@ The following will compress */var/log/friendica* (assuming this is the location
 To monitor the health status of your Friendica installation, you can use for example a tool like Zabbix. Please define 'stats_key' in your local.config.php in the 'system' section to be able to access the statistics page at /stats?key=your-defined-stats_key
 
 The statistics contain data about the worker performance, the last cron call, number of reports, inbound and outbound packets, posts and comments.
+
+### Prometheus
+
+To use [prometheus](https://prometheus.io) for gathering metrics, use the [Friendica exporter](https://git.friendi.ca/friendica/friendica-exporter).
+
+You can find the installation instructions here: https://git.friendi.ca/friendica/friendica-exporter#installation