def primary(value = nil, options = {}, &block)
      add_css_class!(options, "btn-primary")
      submit(value, options, &block)
    end
def primary(value = nil, options = {}, &block)
      add_css_class!(options, "btn-primary")
      submit(value, options, &block)
    end
Same as submit button, only with btn-primary class added