Forum crashes on empty post

[JeremySilverTongue]

In forum.py, it seems that POST() is trying to check if the post contains no content, and avoid saving it in that case, however when submitting a blank post, I get the following error, which would suggest that the empty post checking is failing.

Traceback (most recent call last):
  File "/usr/lib/python2.7/wsgiref/handlers.py", line 85, in run
    self.result = application(self.environ, self.start_response)
  File "forum.py", line 95, in Dispatcher
    return DISPATCH[page](env, resp)
  File "forum.py", line 73, in Post
    content = fields['content'][0]