added cadvisor

Cadvisors suggested setup didn't work. I followed this suggestion:
google/cadvisor#2838 (comment)

docker-compose.yaml

@@ -16,3 +16,32 @@ services:
       - --config.file=/etc/prometheus/prometheus.yml
     volumes:
       - ./prometheus.yml:/etc/prometheus/prometheus.yml:ro
+    depends_on:
+      - cadvisor
+  # cadvisor:
+  #   image: gcr.io/cadvisor/cadvisor:latest
+  #   container_name: cadvisor
+  #   ports:
+  #     - 8080:8080
+  #   volumes:
+  #     - /:/rootfs:ro
+  #     - /var/run:/var/run:rw
+  #     - /sys:/sys:ro
+  #     - /var/lib/docker/:/var/lib/docker:ro
+
+  cadvisor:
+    image: gcr.io/cadvisor/cadvisor:v0.45.0
+    container_name: cadvisor
+    privileged: true
+    devices:
+      - /dev/kmsg:/dev/kmsg
+    ports:
+      - 8080:8080
+    volumes:
+      - /var/run:/var/run:ro
+      - /sys:/sys:ro
+      - /var/lib/docker/:/var/lib/docker:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+      - /etc/machine-id:/etc/machine-id:ro
+      - /var/lib/dbus/machine-id:/var/lib/dbus/machine-id:ro
+    restart: unless-stopped

prometheus.yml

@@ -15,3 +15,7 @@ scrape_configs:
     scrape_interval: 5s
     static_configs:
       - targets: ['app:5001']
+  - job_name: cadvisor
+    scrape_interval: 5s
+    static_configs:
+      - targets: ['cadvisor:8080']