anchor.diff:              not the same as DOCKER_REPO because we use the
               https://hub.docker.com/u/postgrestbot account for uploading to dockerhub.
             '';
  +        args = [
  +          "ARG_USE_ENV([DOCKER_USER], [], [DockerHub user name])"
  +          "ARG_USE_ENV([DOCKER_PASS], [], [DockerHub password])"
  +        ];
         }
         ''
  +        # ARG_USE_ENV only adds defaults or docs for environment variables
  +        # We manually implement a required check here
  +        # See also: https://github.com/matejak/argbash/issues/80
  +        DOCKER_USER="''${DOCKER_USER:?DOCKER_USER is required}"
  +        DOCKER_PASS="''${DOCKER_PASS:?DOCKER_PASS is required}"
  +
           docker login -u "$DOCKER_USER" -p "$DOCKER_PASS"
         '';
   
  
positive.code: { buildEnv
  , curl
  , envsubst
  , ghr
  , jq
  , postgrest
  , docker
  , runCommand
  , checkedShellScript
  }:
  let
    github =
  
negative.code:       {
          name = "postgrest-release-dockerhubdescription";
          docs = "Update the repository description on Docker Hub.";
          args = [
            "ARG_USE_ENV([DOCKER_USER], [], [DockerHub user name])"
            "ARG_USE_ENV([DOCKER_PASS], [], [DockerHub password])"
            "ARG_USE_ENV([DOCKER_REPO], [], [DockerHub repository])"
          ];
        }
        ''
          # ARG_USE_ENV only adds defaults or docs for environment variables
          # We manually implement a required check here
          # See also: https://github.com/matejak/argbash/issues/80
          DOCKER_USER="''${DOCKER_USER:?DOCKER_USER is required}"
          DOCKER_PASS="''${DOCKER_PASS:?DOCKER_PASS is required}"
          DOCKER_REPO="''${DOCKER_REPO:?DOCKER_REPO is required}"
  
          # Login to Docker Hub and get a token.
          token="$(
            ${curl}/bin/curl -s \
  