Precompiling assets doesn't seem to be working - ruby-on-rails

Question

I'm having a strange problem that I have never encountered when deploying my rails apps to production.
I run:
bundle exec rake assets:precompile
This is the output:
/home/ubuntu/.rvm/rubies/ruby-2.0.0-p0/bin/ruby /home/ubuntu/.rvm/gems/ruby-2.0.0-p0/bin/rake assets:precompile:all RAILS_ENV=production RAILS_GROUPS=assets
/home/ubuntu/.rvm/rubies/ruby-2.0.0-p0/bin/ruby /home/ubuntu/.rvm/gems/ruby-2.0.0-p0/bin/rake assets:precompile:nondigest RAILS_ENV=production RAILS_GROUPS=assets
This is my app/assets/javascripts/application.js:
//= require jquery
//= require jquery_ujs
//= require jquery.ui.all
//= require twitter/bootstrap
//= require_tree .
And this is my app/assets/stylesheets/application.css:
/*
*= require_self
*= require jquery.ui.all
*= require_tree .
*/
After I precompile, this is my public/assets/application-946a5a61f067fe19fe65ffd12f8c4a20.js
//= require jquery
//= require jquery_ujs
//= require jquery.ui.all
//= require twitter/bootstrap
//= require_tree .
So it's exactly the same as the original file.
And public/assets/application-df7525e917401704ef453cb56bf16697.css is an empty file.
This is my Gemfile:
source 'http://rubygems.org'
gem 'rails', '3.1.1'
# Bundle edge Rails instead:
# gem 'rails', :git => 'git://github.com/rails/rails.git'
gem 'pg'
gem 'settingslogic'
gem 'jquery-rails'
gem 'jquery-ui-rails'
gem 'json'
gem 'will_paginate', '~>3.0.pre2'
gem 'friendly_id', '~> 4.0.0.beta14'
gem 'rails3-jquery-autocomplete'
gem 'omniauth'
gem 'omniauth-twitter'
gem 'omniauth-facebook'
gem 'paperclip', '~> 3.0'
gem 'public_activity'
gem 'rails-timeago'
gem 'therubyracer', :require => 'v8'
gem 'less-rails'
gem 'twitter-bootstrap-rails', :git => 'git://github.com/seyhunak/twitter-bootstrap-rails.git'
# Gems used only for assets and not required
# in production environments by default.
group :assets do
gem 'sass-rails'
gem 'coffee-rails'
gem 'uglifier', '>= 1.0.3'
end
# To use ActiveModel has_secure_password
# gem 'bcrypt-ruby', '~> 3.0.0'
# Use unicorn as the web server
# gem 'unicorn'
# Deploy with Capistrano
# gem 'capistrano'
# To use debugger
# gem 'ruby-debug19', :require => 'ruby-debug'
group :test do
# Pretty printed test output
gem 'turn', :require => false
end
And config/environments/production.rb:
Yupp::Application.configure do
# Settings specified here will take precedence over those in config/application.rb
# Code is not reloaded between requests
config.cache_classes = true
# Full error reports are disabled and caching is turned on
config.consider_all_requests_local = false
config.action_controller.perform_caching = true
# Disable Rails's static asset server (Apache or nginx will already do this)
config.serve_static_assets = false
# Compress JavaScripts and CSS
config.assets.compress = true
# Don't fallback to assets pipeline if a precompiled asset is missed
config.assets.compile = false
# Generate digests for assets URLs
config.assets.digest = true
#config.assets.initialize_on_precompile = false
#...
end
Any direction will be greatly appreciated.

Answer 1

What solved the problem for me :
set the last rails version in Gemfile (3.2.14 for now)
bundle update
bundle install
restart the app touch tmp/restart.txt

Answer 2

I spent 2 hours on this then I found https://github.com/sstephenson/sprockets/issues/352
I tried downgrade ruby to 1.9.3 and do precompile then add compiled files to repo.. This isn't what I want but it works..
Update: what rails version are you using ? I was using 3.2.2 which has problem like this. 3.2.13 works fine(with ruby 2.0).