Issues creating a project-specific rvm gemset

gistfile1.txt

My rails_apps_composer gem creates an application template from 
various "recipes" (similar to Michael Bleigh’s RailsWizard gem):
https://github.com/RailsApps/rails_apps_composer

I've got a recipe that creates a project-specific rvm gemset.

Quite a few users use the recipe without problems but several 
have reported errors. I'm not able to identify the source of the errors.

I'd like to get some help. First, to review my code and identify 
any obvious errors. Second, for suggestions about how I might 
help my users diagnose system configuration issues that might 
be causing the errors.

My application template (Thor commands) contains this code:

````
  app_name = 'myapp'
  if ENV['MY_RUBY_HOME'] && ENV['MY_RUBY_HOME'].include?('rvm')
    begin
      gems_path = ENV['MY_RUBY_HOME'].split(/@/)[0].sub(/rubies/,'gems')
      ENV['GEM_PATH'] = "#{gems_path}:#{gems_path}@global"
      require 'rvm'
      RVM.use_from_path! File.dirname(File.dirname(__FILE__))
    rescue LoadError
      raise "RVM gem is currently unavailable."
    end
  end
  RVM.gemset_create app_name
  run "rvm rvmrc trust"
  begin
    RVM.gemset_use! app_name
  rescue StandardError
    raise "rvm failure: unable to use gemset #{app_name}"
  end
````

How can I improve the code for improved failure diagnostics?

Here I've got an issue without sufficient details to diagnose or resolve:
https://github.com/RailsApps/rails-composer/issues/14

Thanks!