Add documentation about Telemetry configuration

docs/configuring-playbook-telemetry.md

@@ -0,0 +1,14 @@
+# Enabling Telemetry for your Matrix server
+
+By default, this playbook configures your Matrix homeserver to not send any telemetry data anywhere.
+
+The [matrix.org](https://matrix.org) team would really appreciate it if you could help the project out by reporting
+anonymized usage statistics from your homeserver. Only very basic aggregate
+data (e.g. number of users) will be reported, but it helps track the
+growth of the Matrix community, and helps to make Matrix a success.
+
+If you'd like to **help by enabling submission of anonymized usage statistics** for your homeserver, add this to your configuration file (`inventory/matrix.<your-domain>/vars.yml`):
+
+```yaml
+matrix_synapse_report_stats: true
+```

docs/configuring-playbook.md

@@ -23,6 +23,8 @@ When you're done with all the configuration you'd like to do, continue with [Ins
 
 ## Other configuration options
 
+- [Enabling Telemetry for your Matrix server](configuring-playbook-telemetry.md) (optional)
+
 - [Controlling Matrix federation](configuring-playbook-federation) (optional)
 
 - [Adjusting email-sending settings](configuring-playbook-email.md) (optional)