Fixed error message for bootstrap 3

Author: Nikolay Moskvin

app/helpers/rails_admin/form_builder.rb

@@ -45,15 +45,17 @@ def field_wrapper_for(field, nested_in)
     end
 
     def input_for(field)
-      @template.content_tag(:div, class: 'col-sm-10 controls') do
+      css = 'col-sm-10 controls'
+      css += ' has-error' if field.errors.present?
+      @template.content_tag(:div, class: css) do
         field_for(field) +
         errors_for(field) +
         help_for(field)
       end
     end
 
     def errors_for(field)
-      field.errors.present? ? @template.content_tag(:span, field.errors.to_sentence, class: 'help-inline') : ''.html_safe
+      field.errors.present? ? @template.content_tag(:span, field.errors.to_sentence, class: 'help-inline text-danger') : ''.html_safe
     end
 
     def help_for(field)

app/views/layouts/rails_admin/pjax.html.haml

@@ -6,6 +6,7 @@
 .page-header
   %h1= @page_name
 - flash && flash.each do |key, value|
+  - key = 'danger' if key == 'error'
   .alert{class: "alert-#{key}"}
     %a.close{href: '#', :'data-dismiss' => "alert"} ×
     = value