Made ban object show IP in 'str' method instead of 'unicode' which was user

with python2

boards/models/user.py

@@ -16,5 +16,5 b' class Ban(models.Model):'
                               max_length=BAN_REASON_MAX_LENGTH)
     can_read = models.BooleanField(default=True)
 
-    def __unicode__(self):
+    def __str__(self):
         return self.ip