title: Compare two records and get the names of the changed columns in rails active record
body: <p>i need to compare two active records and get the name of the changed column</p>
  
  <pre><code>#&lt;Evaluation id: 1, name: "Foo", status: "yes", comments: "can be better", created_at: "2017-05-09 12:00:00", updated_at: "2017-05-09 12:00:00"&gt;    
  #&lt;Evaluation id: 2, name: "Foo", status: "yes", comments: "keep up the good work", created_at: "2017-05-09 12:05:00", updated_at: "2017-05-09 12:05:00"&gt;
  </code></pre>
  
  <p>I need to compare these two records and get the names of the changed columns. In this case <code>:comments, :created_at, :updated_at</code></p>
  
  <p>I have tried using methods like <code>eql?</code>, <code>record1.attributes.except('id') == record2.attributes.except('id')</code></p>
  
  <p>These only return either true or false I need to get the column names as well.
  This can be done by comparing each column but i am looking for any other option.</p>