Update setup_install.yml

roles/matrix-synapse/tasks/synapse/setup_install.yml

@@ -144,3 +144,12 @@
           }
         ]
       }}
+
+- name: Generate sample prometheus.yml for external scraping
+  template:
+    src: "{{ role_path }}/templates/synapse/prometheus/external_prometheus.yml.example.j2"
+    dest: "{{ matrix_synapse_base_path }}/external_prometheus.yml.example"
+    owner: "{{ matrix_user_username }}"
+    group: "{{ matrix_user_groupname }}"
+    mode: 0644
+  when: matrix_synapse_metrics_proxying_enabled|bool