Getting started edits

These two proposed edits are based upon feedback I've gotten from participants:

- I've often been asked what `-T` means when generating the Rails app
- I've often been asked what `g` meant in the rails command and why `body` needs a data type but `title` does not.
Sounds good to me.  The more English and the less jargon, the better.

How about:

"1. `g` is short for `generate` when using the `rails` command"