anchor.diff:    <div class="control-group <%= validation_class %>">
       <%= f.label :last_name, :class => 'control-label required' %>
       <div class="controls">
  -      <%= f.text_field :last_name, :class => "input-xxlarge required" %>
  +      <%= f.text_field :last_name, :class => "input-xxlarge required", required: true %>
           <span class="help-in-line">
             <%=errors.join (', ')%>
         </span>
  
positive.code: <div class="control-group <%= validation_class%>">
    <%= f.label :email, :class => 'control-label required' %>
    <div class="controls">
      <%= f.text_field :email, :class => 'input-xxlarge required' %>
        <span class="help-in-line">
          <%=errors.join (', ')%>
        </span>
  
negative.code:   <div class="control-group <%= validation_class %>">
      <%= f.label :first_name, :class => 'control-label required' %>
      <div class="controls">
        <%= f.text_field :first_name, :class => "input-xxlarge required", required: true %>
        <span class="help-inline">
          <%= errors.join (', ') %>
        </span>
  