validating at least one checkbox is selected
<p>I'm trying to validate that at least one checkbox in the form has been checked, however it's not currently working. </p>

<p>This is what my controller looks like: </p>

<pre><code>class UserExpertise &lt; ActiveRecord::Base
  belongs_to :user
  validate :atleast_one_is_checked

  def atleast_one_is_checked
    errors.add(:base, "Select at least one expertise") unless :gardening || :cooking || :cleaning || :washing_up
  end
end
</code></pre>

<p>However, no error shows up when none of them are selected. Incidentally, if instead I were to remove the 'unless' portion of the code, as follows, an error shows all the time, regardless of how many or how few are selected. </p>

<pre><code>  def atleast_one_is_checked
    errors.add(:base, "Select at least one expertise") 
  end
end
</code></pre>

<p>I can't get validation that at least one checkbox has been selected though, as the above does not seem to work. Any help would be appreciated! </p>