title: Sorting by a field of another table referenced by a foreign key in SQLObject
body: <p>Is it possible to sort results returned by SQLObject by a value of another table?</p>
  
  <p>I have two tables:</p>
  
  <pre><code>    class Foo(SQLObject):
          bar = ForeignKey('Bar')
  
      class Bar(SQLObject):
          name = StringCol()
          foos = MultipleJoin('Foo')
  </code></pre>
  
  <p>I'd like to get <code>foo</code>s sorted by the <code>name</code> of a <code>bar</code> they are related to.</p>
  
  <p>Doing:</p>
  
  <pre><code>    foos = Foo.select().orderBy(Foo.q.bar)
  </code></pre>
  
  <p>...would sort the output by <code>bar</code>'s ids, but how do I sort them by <code>bar</code>'s name?</p>