Q:

Rails 3 validation: two available checkboxes, can't check them both

I have a very simple object that needed an approved checkbox and a Declined checkbox
How can I check to make sure that both aren't checked? 
A user should only check one, not both. 

A:

As @Christopher Marshall pointed out - this functionality is accomplished by the radio button type.  Just change type="checkbox" to type="radio" and make sure the name is the same 

