Docker to be configured to hit local registry and not

I have two things to achieve:
1)I have created a local registry i.e. localhost:5000. So I wanted to configure docker such that whenever I am pushing and pulling the images it should be done from this local registry and should not hit

2)Also I need to tag the image before pushing the image
docker tag ubuntu localhost:5000/ubuntu
Then need to push
docker push localhost:5000/ubuntu

I do not want localhost:5000 to be tagged.
Is there a way I can directly push the image just using the name of the image without tagging it?