If you're using Homebrew, just run brew install hub and you should be all set with auto-completion.
Open your .bashrc file if you're on Linux, or your .bash_profile if you're on OS X and add:
if [ -f /path/to/hub.bash_completion ]; then
. /path/to/hub.bash_completion
fiCreate a new folder for completions:
mkdir -p ~/.zsh/completionsCopy the file /etc/hub.zsh_completion from the location where you downloaded hub to the folder ~/.zsh/completions/ and rename it to _hub:
cp /path/to/etc/hub.zsh_completion ~/.zsh/completions/ \
mv ~/.zsh/completions/hub.zsh_completion ~/.zsh/completions/_hubThen add the following lines to your .zshrc file:
fpath=(~/.zsh/completions $fpath)
autoload -U compinit && compinit