Tag runners.

Tag with the runner name (useful for deployments so I don't have to copy
files over SSH).

docker-compose.yml

@@ -9,6 +9,7 @@ services:
       DOCKER_IMAGE: docker:19.03
       REGISTRATION_TOKEN: "${REGISTRATION_TOKEN}"
       RUNNER_NAME: "${RUNNER_NAME}"
+      RUNNER_TAG_LIST: "${RUNNER_NAME}"
     image: adarnimrod/gitlab-runner
     restart: always
     volumes: