Add additional lines to get autocompletion to work in zsh

[samg]

@aharris88 could you take a look at this and confirm these are correct? I'm not a zsh user.

Thanks!

[agarrharr]

Yeah, that looks good, but I would probably word it similar to the way you did with bash

If it isn't already, add the following to your .zshrc:

autoload -U compinit
compinit

Then add this to source the completions:

fpath=(/path/to/timetrap-1.x.y/gem/completions/zsh $fpath)