title: Bookshelf relations aren't working as expected
body: <p>I have 4 tables simplified as follows:  </p>
  
  <p><strong>Tables</strong>  </p>
  
  <pre><code>event:     id, location_id  
  location:  id  
  user:      id  
  eventUser: event_id, user_id
  </code></pre>
  
  <p><strong>Relations</strong>  </p>
  
  <pre><code>Event hasOne Location  
  Event belongsToMany Users
  
  Location belongsTo Event
  
  User belongsToMany Events
  
  EventUser belongsToMany Events  
  EventUser belongsToMany Users
  </code></pre>
  
  <p><strong>I want to get Events with Locations given a User id</strong>  </p>
  
  <p>One example of what I've tried:</p>
  
  <pre><code>EventUser.forge().where({user_id: 1}).fetchAll({withRelated: ['Event', 'Event.Location']})
  </code></pre>
  
  <p>But I can't get it to return any events.</p>
  
  <p>Is my set up correct?</p>