Using

docker run -it --rm iron/mono mono --version

Building this image

docker build -t iron/mono:latest .

Tag the version, check it with docker run --rm iron/mono mono --version:

docker tag -f iron/mono:latest iron/mono:X
docker tag -f iron/mono:latest iron/mono:X.Y
docker tag -f iron/mono:latest iron/mono:X.Y.Z

Push:

docker push iron/mono