completion is not compatible with zsh

[ssbarnea]

If your shell is zsh, you cannot use eval "$(gerrit completion)" because completion command does not exists.

[shanesmith]

Yup that's true, it is currently only written for bash. It's a pretty simple script though so I'll take a shot at converting it to zsh... unless you happen to know all about zsh completion and would like to contribute? =)