Update verification step to use RSPV script

> I think those commands are worthwhile to run (they'll have to use them later on in life) but we should check if the versions match up with what we're teaching.
>
> Adding the following command at the end should be good though:
>
> curl -s http://railsbridge-montreal.com/checks/script | ruby -
>
> The output should be as follows:
>
> You have the prerequisites installed for the following classes:
> Introduction to programming: Yes
> Introduction to Rails: Yes
> Rails for Developers: Yes