= form_for [@project, @user], html: {class: 'form-horizontal'} do |user_form|
  %fieldset
    %legend 
      .control-group
        = user_form.label :nickname, 'nickname', class: 'control-label'
        .controls
          = user_form.text_field :nickname
      .form-actions
        = user_form.submit 'Add User', class: 'btn btn-primary'