Add warning to the migration

priv/repo/migrations/20200811143147_ap_id_not_null.exs

@@ -2,6 +2,8 @@ defmodule Pleroma.Repo.Migrations.ApIdNotNull do
   use Ecto.Migration
 
   def up do
+    Logger.warn("If this migration fails please open an issue at https://git.pleroma.social/pleroma/pleroma/-/issues/new \n")
+
     alter table(:users) do
       modify(:ap_id, :string, null: false)
     end