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