title: Django: Does unique_together imply db_index=True in the same way that ForeignKey does?
body: <p>A field on a model, <code>foo = models.ForeignKey(Foo)</code> will automatically add a database index for the column, in order to make look-ups faster. That's good and well, but Django's docs don't state whether the fields in a model-meta's <code>unique_together</code> receive the same treatment. I happen to have a model in which one char field which is listed in <code>unique_together</code> requires an index for quick lookups. I know that it won't hurt anything to add a duplicate <code>db_index=True</code> in the field definition, but I'm curious.</p>