title: Rails edit serialized JSON data
body: <p>I have a column that stores JSON data. I don't know how to show it when it is on Edit state.</p>
  
  <pre><code> serialize :value, JSON
  
   = f.fields_for :value do |ff|
      .form-group
        = ff.label :short  
        = ff.text_field :short, class: 'form-control'
      .form-group
        = ff.label :long
        = ff.text_field :long, class: 'form-control'
  </code></pre>