title: Specify environment variables for bundle exec
body: <p>I have seen two different ways to specify environment variables when execute <code>bundle exec</code>. Which one is correct on Linux? Maybe both? I am looking for general answer, I know that in this particular case (updating Redmine) specifying RAILS_ENV may be even unnecessary.</p>
  <pre><code>bundle exec rake db:migrate RAILS_ENV=production
  </code></pre>
  <pre><code>RAILS_ENV=production bundle exec rake db:migrate
  </code></pre>