mongodb needs 0.5 GB for a fresh install. Half of this goes to
kombu.

kombu could use redis or some other transport (see
`#322 </issues/322>`_), so fixing `#322 </issues/322>`_ will help
this issue too.

mongodb database files contain a lot of NUL bytes. So one can
easily use sparse files to save space on disk:

::

     # service mongodb stop
     # cd /var/lib/
     # cp -a --sparse=always mongodb mongodb.new
     # mv mongodb mongodb.old
     # mv mongodb.new mongodb
     # service mongodb start
     # # TEST mongodb
     # rm -rf mongodb.old

Maybe later versions of mongodb do this already internally. The
above was needed on mongodb from debian/stable.

Documenting the "make sparse" possibility will also help this
issue.

We should treat ``/u/aaron/`` the same as ``/u/aaron`` rather than
returning a 404. (Should this be true of URLs ending in a file
extension or not?)

We need a nice paginator. We may also need a wrapper paginator task
(or just a specialized paginator) for mongodb queries.

`http://flask.pocoo.org/snippets/44/ <http://flask.pocoo.org/snippets/44/>`_
would be a good starting point


-  Add paginator(s)
-  Make sure said paginator works efficiently with mongodb/mongokit
   queries
-  add tests