title: Storing user preference from collection of checkboxes
body: <p>I have a collection of checkboxes of names that a user can select multiple of. </p>
  
  <p>I want to save the users selection for the next time they login. </p>
  
  <p>However, over time some names may get removed while new ones may get added. Added names can remain unchecked, but I wouldn't want to keep storing IDs of deleted names. </p>
  
  <p>So how should I go about this?</p>