Make obvious and integrate HTML5 "required" attribute

The HTML5 "required" attribute, as it's name implies, tells the aware-browsers, that they shouldn't submit the form is a field marked with this attribute isn't filled in. Currently, I can achieve the behaviour using rails, by passing a

  :required => true

to any helper which actually generates:

 ... required="required"

markup.

The HTML5 specs tell you that the value of the attribute doesn't matter, but I still believe is more concise to make it generate markup like this:

  <input type="text" name="sample" required />

The same for the other attributes such as autofocus, disabled, and the like.

I mean to be able to do something like this:

def test_required_text_field_tag
    expected = %{<input name="name" id="name" type="text" required />}
    assert_dom_equal(expected, text_field_tag(:name, :required => true)
end