title: how can i run bundle install elsewhere?
body: <pre><code>$ git push heroku master
  Counting objects: 70, done.
  Delta compression using up to 4 threads.
  Compressing objects: 100% (61/61), done.
  Writing objects: 100% (70/70), 16.06 KiB | 0 bytes/s, done.
  Total 70 (delta 2), reused 0 (delta 0)
  
  -----&gt; Ruby app detected
  -----&gt; Compiling Ruby/Rails
  -----&gt; Using Ruby version: ruby-2.0.0
  -----&gt; Installing dependencies using Bundler version 1.3.2
         New app detected loading default bundler cache
         Running: bundle install --without development:test --path vendor/bundle --binstubs vendor/bundle/bin --deployment
         You are trying to install in deployment mode after changing
         your Gemfile. Run `bundle install` elsewhere and add the
         updated Gemfile.lock to version control.
         You have added to the Gemfile:
         * pg
         * rails_12factor
         Bundler Output: You are trying to install in deployment mode after changing
         your Gemfile. Run `bundle install` elsewhere and add the
         updated Gemfile.lock to version control.
  
         You have added to the Gemfile:
         * pg
         * rails_12factor
   !
   !     Failed to install gems via Bundler.
   !
  
   !     Push rejected, failed to compile Ruby app
  
  To git@heroku.com:obscure-reaches-5507.git
   ! [remote rejected] master -&gt; master (pre-receive hook declined)
  error: failed to push some refs to 'git@heroku.com:obscure-reaches-5507.git'
  </code></pre>
  
  <p>how can i solve this problem?</p>