Separate selected from available stars

Scenario:
- Using the rating_for_user method
- User has previously rated an object and reloaded the page

Problem:
The number of available stars now matches the previous rating (as opposed to the number of stars in the option hash specified or the default value of 5). For example if the previous rating was 3, there are only 3 out of 5 stars shown and the rating can't be changed to anything above 3 stars.