[COOK-3059] : add bundle_options attribute to rails resource

Allows arbitrary code to be appended to the bundler command string
which is useful to be able to capture output to a specific log
using the 'tee' command for example:

        bundle_options "2>&1 | tee -a \some\log\file.log"
Fix method scoping on two sub-resources within the callback.

Looks like the run context for the deploy resource callbacks has changed (or this just never worked).
Update README.md