Merge branch 'feature/delivery-tracking' into 'develop'

Track signed fetches of objects and use them for delete federation

See merge request pleroma/pleroma!1661

priv/repo/migrations/20190912065617_create_deliveries.exs

@@ -0,0 +1,12 @@
+defmodule Pleroma.Repo.Migrations.CreateDeliveries do
+  use Ecto.Migration
+
+  def change do
+    create_if_not_exists table(:deliveries) do
+      add(:object_id, references(:objects, type: :id), null: false)
+      add(:user_id, references(:users, type: :uuid, on_delete: :delete_all), null: false)
+    end
+    create_if_not_exists index(:deliveries, :object_id, name: :deliveries_object_id)
+    create_if_not_exists(unique_index(:deliveries, [:user_id, :object_id]))
+  end
+end