docker build . -t git
you need to mount the /output to access files like in
docker run -v ${PWD}:/output git clone https://github.com/jeanlaurent/redirect-custom-handler.git
If you need to clone private repository you have to mount your ~/.ssh
docker run -v ${PWD}:/output -v ${HOME}/.ssh/:/root/.ssh git clone [email protected]:jeanlaurent/redirect-custom-handler.git