def btn_group(tag: :div, vertical: false, **options, &block)
      class_str = 'btn-group'
      class_str << ' btn-group-vertical' if vertical

      content_tag(tag, nil, merge_predef_class(class_str, options), &block)
    end
def btn_group(tag: :div, vertical: false, **options, &block)
      class_str = 'btn-group'
      class_str << ' btn-group-vertical' if vertical

      content_tag(tag, nil, merge_predef_class(class_str, options), &block)
    end
Dropdown menus not implemented
 Public: Button group, combine buttons as a group

 tag      - Symbol or String. Html tag of button group. ( default: :div )
 vertical - Boolean. Buttons align vertically. ( default: false )
 options  - Other options can be accepted by the tag specified.
            ( default: {} )
 block    - The content of a button group, usually are several links with
            button styles.

 Examples

   = bg do
     = link_to('button 1', '#', class: 'btn')
     = link_to('button 2', '#', class: 'btn')
     = link_to('button 3', '#', class: 'btn')

 Returns the whole button group.