title: How to make a field required in Rails?
body: <p>What is the simplest way to make a field required in Rails?</p>
  
  <p>inquiry.rb:</p>
  
  <pre><code>class Inquiry &lt; ActiveRecord::Base
    attr_accessible :address, :email_id, :gender, :message, :mobile_number, :name
  end
  </code></pre>