Bootstrap3対応

application.html.haml

    = stylesheet_link_tag '//netdna.bootstrapcdn.com/bootstrap/3.0.0/css/bootstrap-glyphicons.css'
    = stylesheet_link_tag '//netdna.bootstrapcdn.com/bootstrap/3.0.0/css/bootstrap.min.css'
    = stylesheet_link_tag '//netdna.bootstrapcdn.com/font-awesome/3.2.1/css/font-awesome.min.css'

Gemfile

gem 'simple_form', git: 'git://github.com/zlx/simple_form', branch: 'feature/integration_bootstrap3'
gem 'twitter-bootstrap-rails', git: 'git://github.com/seyhunak/twitter-bootstrap-rails.git', branch: 'bootstrap3'

simple_form_bootstrap3.rb

SimpleForm.setup do |config|
  config.wrappers :bootstrap3, tag: 'div', class: 'form-group', error_class: 'error' do |b|
    b.use :html5
    b.use :placeholder
    b.use :label
    b.wrapper :controls, tag: 'div', class: 'col-sm-9' do |ba|
      ba.use :input
      ba.use :error, wrap_with: { tag: 'span', class: 'help-inline' }
      ba.use :hint,  wrap_with: { tag: 'p', class: 'help-block' }
    end
  end

  config.wrappers :prepend, tag: 'div', class: "control-group", error_class: 'error' do |b|
    b.use :html5
    b.use :placeholder
    b.use :label
    b.wrapper tag: 'div', class: 'controls' do |input|
      input.wrapper tag: 'div', class: 'input-prepend' do |prepend|
        prepend.use :input
      end
      input.use :hint,  wrap_with: { tag: 'span', class: 'help-block' }
      input.use :error, wrap_with: { tag: 'span', class: 'help-inline' }
    end
  end

  config.wrappers :append, tag: 'div', class: "control-group", error_class: 'error' do |b|
    b.use :html5
    b.use :placeholder
    b.use :label
    b.wrapper tag: 'div', class: 'controls' do |input|
      input.wrapper tag: 'div', class: 'input-append' do |append|
        append.use :input
      end
      input.use :hint,  wrap_with: { tag: 'span', class: 'help-block' }
      input.use :error, wrap_with: { tag: 'span', class: 'help-inline' }
    end
  end

  # Wrappers for forms and inputs using the Twitter Bootstrap toolkit.
  # Check the Bootstrap docs (http://twitter.github.com/bootstrap)
  # to learn about the different styles for forms and inputs,
  # buttons and other elements.
  config.default_wrapper = :bootstrap3
  config.button_class = 'btn btn-default'
  config.error_notification_class = 'alert alert-danger'
  config.label_class = 'col-sm-3 control-label'
  config.input_class = 'form-control'
end

twitter-bootstrap-railsはhelper使うだけですね

なるほど、参考にしますです。
どうもありがとう！