Allow Mongo Aggregation to use disk for temporary space. (#297)
Allow Mongo Aggregation to use disk for temporary space. (#297)

Aggregations are limited to 100MiB otherwise.

Some of the ranking aggregations using `includeArrayIndex` exceed this
limit, so we should allow disk usage to be able to overcome.
igrigorik/vimgolf,igrigorik/vimgolf,igrigorik/vimgolf,igrigorik/vimgolf