Files are uploaded to S3 if the ENV variables are set (Heroku-friendly)

Gemfile

@@ -36,6 +36,7 @@ gem 'magent', :git => 'http://github.com/dcu/magent.git'
 #File uploading
 gem 'carrierwave', :git => 'git://github.com/rsofaer/carrierwave.git' , :branch => 'master' #Untested mongomapper branch
 gem 'mini_magick'
+gem 'aws'
 
 group :test, :development do
   gem 'factory_girl_rails'

Gemfile.lock

@@ -99,6 +99,10 @@ GEM
     arel (1.0.1)
       activesupport (~> 3.0.0)
     autotest (4.3.2)
+    aws (2.3.21)
+      http_connection
+      uuidtools
+      xml-simple
     bcrypt-ruby (2.1.2)
     bson (1.0.7)
     bson_ext (1.0.7)
@@ -126,6 +130,7 @@ GEM
     haml (3.0.18)
     hashie (0.4.0)
     highline (1.6.1)
+    http_connection (1.3.1)
     i18n (0.4.1)
     json (1.4.6)
     lsof (0.3.0)
@@ -218,6 +223,7 @@ GEM
       rack (>= 1.0)
       rack-test (>= 0.5.3)
     will_paginate (3.0.pre2)
+    xml-simple (1.0.12)
 
 PLATFORMS
   ruby
@@ -225,6 +231,7 @@ PLATFORMS
 DEPENDENCIES
   addressable
   autotest
+  aws
   bson (= 1.0.7)
   bson_ext (= 1.0.7)
   bundler (= 1.0.0)

config/initializers/carrierwave.rb

@@ -3,5 +3,13 @@
 #   the COPYRIGHT file.
 
 CarrierWave.configure do |config|
-  config.storage = :file
+  if ENV['S3_KEY'] && ENV['S3_SECRET'] && ENV['S3_BUCKET']
+    config.storage = :s3
+    config.s3_access_key_id = ENV['S3_KEY']
+    config.s3_secret_access_key = ENV['S3_SECRET']
+    config.s3_bucket = ENV['S3_BUCKET']
+    config.cache_dir = "#{Rails.root}/tmp/uploads"
+  else
+    config.storage = :file
+  end
 end