Patch for Rails App Generator - referenced incorrect option in conditional

Hi all,

I was looking through the new rails app generator code and saw that there was now an option for skipping activerecord --skip-activerecord

I noticed, however, that the conditions placed around said condition actually referenced the option as no_activerecord so I've built this patch to use the correct option name.

Simple one liner, but figured it's the kind of thing that is easily overlooked.

Cheers,
Steve