Running rails parallel:spec[4] does not recognize the CPU count

[Bandes]

The documentation and the code itself seems to indicate that if I add a number after the task, it will change the number of CPUs used to run the suite, but when I try this, I get errors like so:

RAILS_ENV=test rake parallel:spec[4]
zsh: no matches found: parallel:spec[4]

Without the brackets, I do not get an error, but it also doesn't limit the CPU count

RAILS_ENV=test rake parallel:spec 4
10 processes for 476 specs, ~ 47 specs per process

I would have expected at least one of these to result in 4 processes for 476 specs, ~120 specs per process (or something around 120, I didn't do the math... :) )

[grosser]

zsh syntax for rake is:

RAILS_ENV=test rake "parallel:spec[4]"

[grosser]

updated the readme to use the ugly but compatible syntax so we can avoid these in the future #942