Improve generated bin/setup

* Make script idempotent.
* Fail fast with install messages and non-zero exit status.
Agreed.

On Tue, Sep 30, 2014 at 4:23 PM, Derek Prior <notifications@github.com>
wrote:

> In templates/bin_setup.erb:
>
> > @@ -21,10 +25,15 @@ bundle exec rake dev:prime
> >  mkdir -p .git/safe
> >
> >  # Pick a port for Foreman
> > -echo "port: <%= config[:port_number] %>" > .foreman
> > +touch .foreman
>
> I don't think we need to touch here. The > or >> (as @jferris
> <https://github.com/jferris> suggests below) will create the file if
> necessary and I think the grep will behave as we'd like if the fie
> doesn't exist as well.
>
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> <https://github.com/thoughtbot/suspenders/pull/412/files#r18253970>.
>