title: How do I upgrade a rails 4.1 app from ruby 1.9.3 to ruby 2.1.5 without using rvm
body: <p>I'm told to update my rails project from ruby version 1.9.3 to 2.1.5 but I don't know how</p>
  
  <p><img src="https://i.stack.imgur.com/I1ZKb.png" alt="2.1.5 is my ruby version"></p>
  
  <p>I updated my gem file to reflect 2.1.5, and then tried bundle install again, it seemed to work mostly...</p>
  
  <p>Then I tried rake db:migrate and it couldn't handle it. so I don't think I "updated correctly"</p>
  
  <p><img src="https://i.stack.imgur.com/eRJqt.png" alt="enter image description here"></p>
  
  <p>I don't have RVM so I didn't know what to do with <a href="https://stackoverflow.com/questions/29505339/how-do-i-upgrade-a-rails-3-2-app-from-ruby-1-9-3-to-ruby-2-1-5-using-rvm">this answer.</a> </p>
  
  <p>Can someone please help me update my code or point me in the right direction?</p>