README

You must be using git and capistrano to deploy your app. Capistrano will place a file in your Rails.root named 'REVISION'. Tested with the following capistrano setting:

set :scm, :git
set :deploy_via, :remote_cache

app_version.rb

# config/initializers/app_version.rb
begin
  APP_VERSION = "0.8.1"
  
  File.open(File.join(Rails.root, "REVISION")) do |f|
    APP_REVISION       = f.read.strip
    APP_REVISION_SHORT = APP_REVISION[0..6]
  end
rescue
  APP_REVISION       = "????"
  APP_REVISION_SHORT = "??"
end