release-docker: add registry option

reana/reana_dev/release.py

@@ -84,9 +84,12 @@ def release_commands():
 )
 @click.option("--user", "-u", default="reanahub", help="DockerHub user name [reanahub]")
 @click.option("--image-name", help="Should the component have a custom image name?")
+@click.option(
+    "--registry", "-r", default="docker.io", help="Registry to use in the image tag"
+)
 @release_commands.command(name="release-docker")
 @click.pass_context
-def release_docker(ctx, component, user, image_name):  # noqa: D301
+def release_docker(ctx, component, user, image_name, registry):  # noqa: D301
     """Release a component on Docker Hub.
 
     \b
@@ -113,13 +116,19 @@ def release_docker(ctx, component, user, image_name):  # noqa: D301
         if not is_component_dockerised(component_):
             cannot_release_on_dockerhub.append(component_)
         is_component_releasable(component_, exit_code=True, display=True)
-        full_image_name = f"{user}/{image_name or component_}"
+        full_image_name = f"{registry}/{user}/{image_name or component_}"
         docker_tag = get_docker_tag(component_)
         run_command(
             f"docker tag {full_image_name}:latest {full_image_name}:{docker_tag}",
             component_,
         )
-        ctx.invoke(docker_push, component=[component_], tag=docker_tag, user=user)
+        ctx.invoke(
+            docker_push,
+            component=[component_],
+            tag=docker_tag,
+            user=user,
+            registry=registry,
+        )
 
     if cannot_release_on_dockerhub:
         click.secho(