Added a back_url field to the Rate for that will store the redirect path.

* Used in the User Administration panel so RatesController can redirect back to
  the panel as needed.

  #1914

spec/controllers/rates_controller_spec.rb

@@ -272,6 +272,13 @@ describe RatesController, "as an administrator" do
         response.should redirect_to(rates_url(:user_id => @user.id))
       end
       
+      it 'should redirect to the back_url if set' do
+        back_url = '/back_to_this_url'
+        Rate.stub!(:new).and_return(mock_rate(:save => true))
+        post :create, :rate => {}, :back_url => back_url
+        response.should redirect_to(back_url)
+      end
+      
     end
     
     describe "with invalid params" do