Prometheus support (#450)

Co-authored-by: nils måsén <nils@piksel.se>
Co-authored-by: MihailITPlace <ya.halo-halo@yandex.ru>
Co-authored-by: Sebastiaan Tammer <sebastiaantammer@gmail.com>

docker-compose.yml

@@ -0,0 +1,43 @@
+version: '3.7'
+
+services:
+  watchtower:
+    container_name: watchtower
+    build:
+      context: ./
+      dockerfile: dockerfiles/Dockerfile.dev-self-contained
+    volumes:
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+    ports:
+      - 8080:8080
+    command: --interval 10 --http-api-metrics --http-api-token demotoken --debug prometheus grafana parent child
+  prometheus:
+    container_name: prometheus
+    image: prom/prometheus
+    volumes:
+      - ./prometheus/:/etc/prometheus/
+      - prometheus:/prometheus/
+    ports:
+      - 9090:9090
+  grafana:
+    container_name: grafana
+    image: grafana/grafana
+    ports:
+      - 3000:3000
+    environment:
+      GF_INSTALL_PLUGINS: grafana-clock-panel,grafana-simple-json-datasource
+    volumes:
+      - grafana:/var/lib/grafana
+      - ./grafana:/etc/grafana/provisioning
+  parent:
+    image: nginx
+    container_name: parent
+  child:
+    image: nginx:alpine
+    labels:
+      com.centurylinklabs.watchtower.depends-on: parent
+    container_name: child
+
+volumes:
+  prometheus: {}
+  grafana: {}