title: Rails new app fails due to permissions
body: <p>I've searched for some time now but can't solve the problem. I'm on a relatively new computer (osx), only created one rails app on it so far. Until now everything went well. I'm now trying to create a new app using</p>
  
  <pre><code>rails new appname
  </code></pre>
  
  <p>This is what the terminal shows me:</p>
  
  <pre><code>      create  
        create  README.rdoc
        create  Rakefile
        create  config.ru
        create  .gitignore
        create  Gemfile
        create  app
        create  app/assets/images/rails.png
        create  app/assets/javascripts/application.js
        create  app/assets/stylesheets/application.css
        create  app/controllers/application_controller.rb
        create  app/helpers/application_helper.rb
        create  app/views/layouts/application.html.erb
        create  app/mailers/.gitkeep
        create  app/models/.gitkeep
        create  config
        create  config/routes.rb
        create  config/application.rb
        create  config/environment.rb
        create  config/environments
        create  config/environments/development.rb
        create  config/environments/production.rb
        create  config/environments/test.rb
        create  config/initializers
        create  config/initializers/backtrace_silencers.rb
        create  config/initializers/inflections.rb
        create  config/initializers/mime_types.rb
        create  config/initializers/secret_token.rb
        create  config/initializers/session_store.rb
        create  config/initializers/wrap_parameters.rb
        create  config/locales
        create  config/locales/en.yml
        create  config/boot.rb
        create  config/database.yml
        create  db
        create  db/seeds.rb
        create  doc
        create  doc/README_FOR_APP
        create  lib
        create  lib/tasks
        create  lib/tasks/.gitkeep
        create  lib/assets
        create  lib/assets/.gitkeep
        create  log
        create  log/.gitkeep
        create  public
        create  public/404.html
        create  public/422.html
        create  public/500.html
        create  public/favicon.ico
        create  public/index.html
        create  public/robots.txt
        create  script
        create  script/rails
        create  test/fixtures
        create  test/fixtures/.gitkeep
        create  test/functional
        create  test/functional/.gitkeep
        create  test/integration
        create  test/integration/.gitkeep
        create  test/unit
        create  test/unit/.gitkeep
        create  test/performance/browsing_test.rb
        create  test/test_helper.rb
        create  tmp/cache
        create  tmp/cache/assets
        create  vendor/assets/javascripts
        create  vendor/assets/javascripts/.gitkeep
        create  vendor/assets/stylesheets
        create  vendor/assets/stylesheets/.gitkeep
        create  vendor/plugins
        create  vendor/plugins/.gitkeep
           run  bundle install
  Fetching gem metadata from https://rubygems.org/...........
  Fetching gem metadata from https://rubygems.org/..
  Resolving dependencies...
  Using rake (10.0.4) 
  Using i18n (0.6.1) 
  Using multi_json (1.7.4) 
  Using activesupport (3.2.13) 
  Using builder (3.0.4) 
  Using activemodel (3.2.13) 
  Using erubis (2.7.0) 
  Using journey (1.0.4) 
  Using rack (1.4.5) 
  Using rack-cache (1.2) 
  Using rack-test (0.6.2) 
  Using hike (1.2.2) 
  Installing tilt (1.4.1) 
  Errno::EACCES: Permission denied - /Library/Ruby/Gems/1.8/build_info/tilt-1.4.1.info
  An error occurred while installing tilt (1.4.1), and Bundler cannot continue.
  Make sure that `gem install tilt -v '1.4.1'` succeeds before bundling.
  </code></pre>
  
  <p>When I enter</p>
  
  <pre><code>gem install tilt -v '1.4.1'
  </code></pre>
  
  <p>I get the following:</p>
  
  <pre><code>ERROR:  While executing gem ... (Gem::FilePermissionError)
      You don't have write permissions for the /Library/Ruby/Gems/1.8 directory.
  </code></pre>
  
  <p>While searching I've found people with similar looking errors but I couldn't find anything solving my specific problem. </p>
  
  <p>I'm using ruby 2.0.0 and rails 2.3.13.</p>
  
  <p>I really stuck and hope someone knows how to fix this. Thanks in advance!</p>
  
  <p><strong>Update:</strong> I noticed, when I run the rails new app command, the terminal asks me</p>
  
  <pre><code>Enter your password to install the bundled RubyGems to your system: 
  </code></pre>
  
  <p>It has never done this before. Is it possible that I kind of have changed something on the system?</p>
  
  <p><strong>Update2:</strong> After using 2+ days on this, as far as I can say, the solution was to completely reinstall the latest versions of ruby and rails.</p>