HTML5 'required' validation in Ruby on Rails forms

I can't see this question anywhere else, it's hopefully a quick and easy one. How can I use HTML5 validators, such as 'required', in my forms (ruby on rails)? Eg, How would this basic form look if I used HTML5 validation in it? ``` <%=form_for @testimonial do |t|%> <dl> <dt><label for="testimonial_rating">Rating</label></dt> <dd><%=t.select :rating, Testimonial.ratings%></dd> <dt><label for="testimonial_content">Comments</label></dt> <dd><%=t.text_area :content, :rows => 3%></dd> <dd><button class="button success">Submit Review</button></dd> </dl> <%end%> ``` It goes without saying that server side validation is still required.