Add option to publish to non DockerHub registry

tools/cd.sh

@@ -6,10 +6,15 @@ if [[ -z "$1" ]]; then echo "Usage: $0 <tag>" >&2; exit 1; fi
 
 set -o errexit
 
+if [[ -z "${DOCKER_REGISTRY}" ]]; then
+  echo "${DOCKER_PASSWORD}" | docker login --username "${DOCKER_USERNAME}" --password-stdin
+else
+  echo "${DOCKER_PASSWORD}" | docker login --username "${DOCKER_USERNAME}" --password-stdin "${DOCKER_REGISTRY}"
+  DOCKER_USERNAME="${DOCKER_REGISTRY}"
+fi
+
 docker build -t "${DOCKER_USERNAME}/doccano:latest" .
 docker build -t "${DOCKER_USERNAME}/doccano:$1" .
 
-echo "${DOCKER_PASSWORD}" | docker login --username "${DOCKER_USERNAME}" --password-stdin
-
 docker push "${DOCKER_USERNAME}/doccano:latest"
 docker push "${DOCKER_USERNAME}/doccano:$1"