How to update dockerhub readme automatically

dockerhub-readme-update.sh

#!/bin/bash
usage() { 
  if [ ! -z $1 ]; then
    echo -e "ERROR:\n" 1>&2
  fi
  echo "Usage: $0 -f /path/to/README.md -u dockerhub-username [-r dockerhub-repo-prefix] -n repo-name" 1>&2
  exit 1; 
}

while getopts ":r:u:f:n:" o; do
    case "${o}" in
        f)
            README_FILE=${OPTARG}
            test -f || usage "README file does not exists"
            README_FILE=$(realpath $README_FILE)
            ;;
        u)
            DOCKERHUB_USERNAME=${OPTARG}
            ;;
        r)
            DOCKERHUB_REPO_PREFIX=${OPTARG}
            ;;
        n)
            DOCKERHUB_REPO_NAME=${OPTARG}
            ;;
        *)
            usage
            ;;
    esac
done
shift $((OPTIND-1))

if [ -z "${README_FILE}" ] || [ -z "${DOCKERHUB_USERNAME}" ] || \
   [ -z "${DOCKERHUB_REPO_NAME}" ] ; then
    usage
fi
echo -n Password:
read -s DOCKERHUB_PASSWORD
echo

docker run --rm -v $README_FILE:/data/README.md \
    -e DOCKERHUB_USERNAME=$DOCKERHUB_USERNAME \
    -e DOCKERHUB_PASSWORD=$DOCKERHUB_PASSWORD \
    -e DOCKERHUB_REPO_PREFIX=$DOCKERHUB_REPO_PREFIX \
    -e DOCKERHUB_REPO_NAME=$DOCKERHUB_REPO_NAME \
     sheogorath/readme-to-dockerhub