rails/rails — pull request #14468 by izoomi (2014-03-24 19:54:48+00:00)
Title: Fix date_select with_css_classes: true option overwriting other html classes

Concatenate 'day' 'month' and 'year' classes rather than overwriting.

When with_css_classes is true it overwrites select_options[:class] predefined values
```ruby
select_options[:class] = type if @options[:with_css_classes]
```