title: Assign custom labels to checkboxes using Formtastic
body: <p>I have a few checkboxes coming from nested model (<code>:admin accepts_nested_attributes_for :account_setting</code>). By default, the label for the checkbox is generated from the model's attributes. But I want to use custom labels which I store in the locales folder as key value pairs.</p>
  
  <p>This is the code,</p>
  
  <pre>
  <code>
  = semantic_form_for(resource, :as => resource_name, :url => registration_path(resource_name), :validate => true, :html => { :method => :put }) do |f|
    = f.input :email
    = f.inputs :receive_email_digest, :as =>:check_boxes, :for => :account_setting, :label => 'My custom label'
  </code>
  </pre>
  
  <p>And it does not work. I tried <code>:input_html, :member_label</code>.</p>
  
  <p>Does formtastic suppor this? Or do we have to hack it?</p>