Correctly render nil config values as empty rather than strings.
Don't explicitly include rails::configure recipe, since it ties this cookbook to the built-in rails-app layer.

Instead, execute the 'restart Rails app APPNAME' resource but allow it to be defined anywhere.
Remove the separate definition and update for newer OpsWorks naming.
Indicate dependency on rails cookbook.
OK, let's not be dependant on rails and not worry about this shit.