Django Template Injection
Use templates to write your own crude implementation of the admin log.
Use that to discover that there are 3 polls insted of 2.
Going to that poll gives you an exception with a code traceback, giving you a hint as to some templates you can use to get the flag.
More detailed, original write-up ( https://github.com/ibnzterrell/ctf-write-ups/blob/master/CSAW_Quals_2017/ShiaLabeouf.md )