compose: Add healthchecks to the peertube app service definition

This commit adds a native healthcheck to the peertube app service using
the nodejs command line interface.

kudos to @3wordchant for the idea :)

compose.yml

@@ -59,6 +59,12 @@ services:
         target: /docker-entrypoint.sh
         mode: 0555
     command: npm start
+    healthcheck:
+      test: 'nodejs -e "http.get(''http://localhost:9000/api/v1/ping'', (res) => { console.log(''status: '', res.statusCode); if (res.statusCode == 200) { process.exit(0); } else { process.exit(1); } });"'
+      interval: 1m
+      timeout: 30s
+      retries: 3
+      start_period: 1m
     entrypoint: /docker-entrypoint.sh
     networks:
       - internal