Data export shouldn't repeat the feed definition for every feed_item

[zackw]

In the attached JSON data export, the feed definition is repeated for every feed_item. This potentially doubles (or more, if many feed_items have been added to multiple feeds!) the length of a large data export. It should be sufficient to dump the ID for each feed. A better JSON structure would be something like

...
"feeds": [ { "id": 2, ... }, ... ]
"feed_items": [
    { "id": 2, "title": "some website", ...,
       "feeds": [ 2, 3, ... ]
    },
    ...
]

tagteam_export_2017-11-27 14_17_21 -0500.json.txt