title: Devise Invitable : Optionally Send Email
body: <p>in devise invitable, you can invite a new user by performing:</p>
  
  <pre><code>User.invite!(:email =&gt; "new_user@example.com", :name =&gt; "John Doe")
  </code></pre>
  
  <p>What I would like to do is (sometimes) prevent devise invitable from sending out an email. I found the following code in the library:</p>
  
  <pre><code>def invite!
          if new_record? || invited?
            self.skip_confirmation! if self.new_record? &amp;&amp; self.respond_to?(:skip_confirmation!)
            generate_invitation_token if self.invitation_token.nil?
            self.invitation_sent_at = Time.now.utc
            save(:validate =&gt; false)
            ::Devise.mailer.invitation_instructions(self).deliver
          end
        end
  </code></pre>
  
  <p>Any ideas on how to best update that to not send out the email on the last line? I'm not familiar with the ::</p>
  
  <p>thanks</p>