Create upvotes in the upvoting user's shard, so we can query for them,
and make the upvote_count and post_count cached counts update properly
cross-shard.
Remove a foreign key constraint that was preventing users on other
shards from posting items to a collection.
Create stream_item_instances on the user's shard, and make sure to query
them from there.
Further work should be done to optimize :include so that we can
efficient pull in the stream items for the instances.
test plan: as a user on one shard, interact with a collection on another
shard -- posting to it, upvoting/downvoting, cloning items from that and
other shards. verify you don't get errors, missing data, or incorrect
counts.
Change-Id: I91aeebd404cd20663a533b2f38c08ec90c65868e
Reviewed-on: https://gerrit.instructure.com/11228
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Cody Cutrer <cody@instructure.com>
Reviewed-by: Simon Williams <simon@instructure.com>
Brian Palmer