simple but a showstopper instruction

Hi @lmartinking,

Thank you for the encouragement. Here's a simple addition to your README file which to me was  showstopper. I'm not a newbie to bash although not as the same level as you (my script still seems to need a lot of polishing). 

It was a minor thing though but after I tried following your instruction, I kind of got lost till I tried to do ./@ and monkey-trail at last ran :)

Anyway, please review and merge if you agree. I have some other functionality ideas for monkey-tail and I'm just polishing it to make it fit your coding style.

SHAMELESS PLUG:  I have a simple bash scripting framework that you might get interest in and make a lot of improvements that you see fit. See https://github.com/icasimpan/shcf

Thanks.
Ismael Casimpan