title: passing a condition to Model.where to find records in rails
body: <p>I have an instance in a method that is like this</p>
  
  <pre><code>@existinguser = User.where("trial_account_made_by = !nil? ")
  </code></pre>
  
  <p>I want to return all users where the trial_account_made_by ( a column in users table) is not nil. How do I pass that to where? </p>