title: Custom Rails Validation not adding 'field_with_errors' wrapper to inputs
body: <p>I'm working on a Rails 4 site with a form that needed some custom validation. But when the validation criteria fails and the error message is shown, the input fields I'm checking aren't given the field_with_errors wrapper. All other fields being validated are getting the wrapper properly, but their validation is a simple presence check on each attribute.</p>
  
  <p>How can I have the wrapper added in with my custom validation?</p>
  
  <p>Additional notes: I'd like to only show my error message once, if possible - but highlight both fields.</p>
  
  <p>In my model: </p>
  
  <pre><code>validate :at_least_one_apply_method
  
  def at_least_one_apply_method
    if [self.apply_url, self.application_instructions].reject(&amp;:blank?).size == 0
      errors[:base] &lt;&lt; ("Please provide at least one: Where to Apply or Applications Instructions.")
    end
  end 
  </code></pre>
  
  <p>Let me know of any other information needed. Thank you!</p>