title: Rails error : active_support/core_ext/string (LoadError)
body: <p>I installed Spree commerce for a website I'm making and needed to upgrade my Ruby version to 2.3.0 I've installed rvm and made the 2.3.0 the default ruby version to use.</p>
  
  <p>I've re-installed Rails and Bundler but when I try to make to add the spree gem to my file using this formula:</p>
  
  <pre><code>    spree install --auto-accept
  </code></pre>
  
  <p>then I get this error : </p>
  
  <pre><code>/Users/steph/.rvm/rubies/ruby-2.3.0/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- active_support/core_ext/string (LoadError)
      from /Users/steph/.rvm/rubies/ruby-2.3.0/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
      from /Users/steph/.rvm/gems/ruby-2.3.0/gems/spree_cmd-3.0.8/lib/spree_cmd/installer.rb:2:in `&lt;top (required)&gt;'
      from /Users/steph/.rvm/rubies/ruby-2.3.0/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
      from /Users/steph/.rvm/rubies/ruby-2.3.0/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
      from /Users/steph/.rvm/gems/ruby-2.3.0/gems/spree_cmd-3.0.8/lib/spree_cmd.rb:13:in `&lt;top (required)&gt;'
      from /Users/steph/.rvm/rubies/ruby-2.3.0/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
      from /Users/steph/.rvm/rubies/ruby-2.3.0/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
      from /Users/steph/.rvm/gems/ruby-2.3.0/gems/spree_cmd-3.0.8/bin/spree:2:in `&lt;top (required)&gt;'
      from /Users/steph/.rvm/gems/ruby-2.3.0/bin/spree:22:in `load'
      from /Users/steph/.rvm/gems/ruby-2.3.0/bin/spree:22:in `&lt;main&gt;'
      from /Users/steph/.rvm/gems/ruby-2.3.0/bin/ruby_executable_hooks:15:in `eval'
      from /Users/steph/.rvm/gems/ruby-2.3.0/bin/ruby_executable_hooks:15:in `&lt;main&gt;'
  </code></pre>
  
  <p>I'm really not sure what to do, i've tried re-installing bundler and rails et spree but nothing different. </p>
  
  <p>I've been following these instructions : <a href="https://guides.spreecommerce.com/developer/getting_started_tutorial.html" rel="nofollow">https://guides.spreecommerce.com/developer/getting_started_tutorial.html</a></p>
  
  <p>Can anyone help me with this error? Thanks in advance!</p>