Used the below command for build-
docker build -t oreng/iojs .
INFO[0000] Get https://index.docker.io/v1/repositories/library/iojs/images: x509: certificate signed by unknown authority.
My DockerFile content is-
FROM iojs:latest
RUN useradd -ms /bin/bash developer
WORKDIR /home/developer
USER developer
Also used the create hub-
Post https://api.github.com/user/repos: x509: certificate signed by unknown authority