title: Heroku push rejected, failed to install gems via Bundler
body: <p>I am struggling to push my code to Heroku. And after searching on Google and Stack Overflow questions, I have not been able to find the solution. Here is What I get when I try "git push heroku master" :</p>
  
  <pre><code>Heroku receiving push
  -----&gt; Rails app detected
  -----&gt; Detected Rails is not set to serve static_assets
         Installing rails3_serve_static_assets... done
  -----&gt; Gemfile detected, running Bundler version 1.0.3
         Unresolved dependencies detected; Installing...
         Fetching source index for http://rubygems.org/
         /usr/ruby1.8.7/lib/ruby/site_ruby/1.8/rubygems/remote_fetcher.rb:300:in `open_uri_or_path': bad response Not Found 404 (http://rubygems.org/quick/Marshal.4.8/mail-2.2.6.001.gemspec.rz) (Gem::RemoteFetcher::FetchError)
          from /usr/ruby1.8.7/lib/ruby/site_ruby/1.8/rubygems/remote_fetcher.rb:172:in `fetch_path'
  .
  ....
  </code></pre>
  
  <p>And finally:</p>
  
  <pre><code>FAILED: http://docs.heroku.com/bundler
   !     Heroku push rejected, failed to install gems via Bundler
  
  error: hooks/pre-receive exited with error code 1
  To git@heroku.com:myapp.git
   ! [remote rejected] master -&gt; master (pre-receive hook declined)
  error: failed to push some refs to 'git@heroku.com:myapp.git'
  </code></pre>
  
  <p>Thanks for your help!</p>