Locating Gem files in deployment isnt always complicated

While struggling to get my application running in deployment with both rvm and bundler, I started getting errors that sass-rails couldn't be loaded.

But sass-rails was in the assets group of the Gemfile, so was bundler including the gems in the assets group?

No.

Turned out that ActiveAdmin was requiring it.  But, because I had it in assets, it wasn't being loaded into my production set of gems.  Solution - move it out of assets.  This was listed in the active_admin documentation, here, but I skimmed right past it -- assuming that the Gemfile would save me.

One more problem:  I couldn't install bcrypt-ruby and couldn't do sudo.  So I tried this in the Gemfile:

gem 'bcrypt-ruby', :require => 'bcrypt'

I picked this idea up from here:  http://stackoverflow.com/a/3901165

Voila!