title: Rails - Validation :if one condition is true
body: <p>On Rails 5. </p>
  
  <p>I have an <code>Order</code> model with a <code>description</code> attribute. I only want to validate it's presence if one of two conditions is met: if the current step is equal to the first step OR if require_validation is equal to true. </p>
  
  <p>I can easily validate based on one condition like this:</p>
  
  <pre><code>validates :description, presence: true, if: :first_step?
  
  def first_step?
   current_step == steps.first
  end
  </code></pre>
  
  <p>but I am not sure how to go about adding another condition and validating if one or the other is true. </p>
  
  <p>something like: </p>
  
  <pre><code>validates :description, presence: true, if: :first_step? || :require_validation
  </code></pre>
  
  <p>Thanks!</p>