title: Rails SQL Query return based on not being in join table
body: <p>I have an <code>Event</code> model. An event can have attendees through the <code>UserEvent</code> join table.</p>
  
  <p>I want a query of events where a specific user id is not an attendee.</p>
  
  <p>I tried <code>Event.joins(:user_events).where('user_events.user_id != ?', user_id)</code> but that clearly doesn't work because if another user attends the Event, it will still list the event because the other user's id clearly isn't equal to <code>user_id</code>. How would I solve this?</p>