title: Ruby on Rails: How to validate a model without Active Record?
body: <p>I'm currently trying to validate fields without having an <code>ActiveRecord::Base</code> inheritance.</p>
  
  <p>My model stores the data on a cache server so I do not need ActiveRecord.</p>
  
  <p>Anyway, I would like to validate the fields of the model like I would if I was using ActiveRecord (e.g <code>validates_numericality_of :quantity, :greater_than =&gt; 0</code>) ?</p>
  
  <p><strong>How can I do that?</strong></p>
  
  <p>Thank you very much for your help.</p>