title: Project stopped working after downgrading Rails version
body: <p>Initially i was using rails version 5.1.1, but when i downgraded it to 4.2.7 then it started giving me the following error:</p>
  
  <pre><code>`method_missing': undefined method `load_defaults'
  </code></pre>
  
  <p>whenever i try to run "rails s" it shows the above error in terminal, it is just a fresh project, i just installed a new project by using "rails new ", then i changed the rails version in gem file to</p>
  
  <pre><code>gem 'rails', '~&gt; 4.2.7'
  </code></pre>
  
  <p>then after doing this when i tried to hit "rails s" it started giving me that error.</p>
  
  <p>Any ideas why is this happening?</p>