support rootless docker in examples (#49)

Author: dgoffredo

examples/hasher/docker-compose.yaml

@@ -3,11 +3,13 @@ services:
     image: datadog/agent
     volumes:
       - '/var/run/docker.sock:/var/run/docker.sock:ro'
+      - '/run/user:/run/user:ro'
       - '/proc/:/host/proc/:ro'
       - '/sys/fs/cgroup/:/host/sys/fs/cgroup:ro'
     environment:
       - DD_API_KEY
       - DD_APM_ENABLED=true
       - DD_LOG_LEVEL=ERROR
+      - DOCKER_HOST
     ports:
       - 8126:8126

examples/http-server/docker-compose.yaml

@@ -43,9 +43,11 @@ services:
         image: datadog/agent
         volumes:
             - '/var/run/docker.sock:/var/run/docker.sock:ro'
+            - '/run/user:/run/user:ro'
             - '/proc/:/host/proc/:ro'
             - '/sys/fs/cgroup/:/host/sys/fs/cgroup:ro'
         environment:
             - DD_API_KEY
             - DD_APM_ENABLED=true
             - DD_LOG_LEVEL=ERROR
+            - DOCKER_HOST