title: Bundler using an older Ruby version
body: <p>I have Ruby 2.3.0 installed in my system. The output of <code>ruby -v</code> is:</p>
  
  <pre><code>ruby 2.3.0p0 (2015-12-25 revision 53290) [x86_64-linux]
  </code></pre>
  
  <p>When I try to run Rails using:</p>
  
  <pre><code>bundle exec rails new ~/my-test-app --dev
  </code></pre>
  
  <p>I get the following error:</p>
  
  <pre><code>Your Ruby version is 2.1.7, but your Gemfile specified 2.3.0
  </code></pre>
  
  <p>I have both Ruby versions installed. How to make bundle use Ruby 2.3.0 instead of 2.1.7</p>