Add migration

priv/repo/migrations/20191026190415_set_not_null_for_activity_expirations.exs

@@ -0,0 +1,15 @@
+defmodule Pleroma.Repo.Migrations.SetNotNullForActivityExpirations do
+  use Ecto.Migration
+
+  # modify/3 function will require index recreation, so using execute/1 instead
+
+  def up do
+    execute("ALTER TABLE activity_expirations
+    ALTER COLUMN activity_id SET NOT NULL")
+  end
+
+  def down do
+    execute("ALTER TABLE activity_expirations
+    ALTER COLUMN activity_id DROP NOT NULL")
+  end
+end