Further preparation for Rails 6 (#15916)

* Use ActiveRecord::Result#to_ary instead of deprecated to_hash

They do the same thing, and to_hash has been removed from Rails 6.1

* Explicitly name polymorphic indexes to workaround a bug in Rails 6.1

cf. https://github.com/rails/rails/issues/41693

* Fix incorrect usage of “foreign_key” in migration script

* Use `ActiveModel::Errors#delete` instead of deprecated clear method

* Fix link headers tests on Rails 6.1

Rails 6.1 adds values to the Link header by default, thus it is not a
LinkHeader object anymore. Fix the test to parse the Link header instead
of assuming it is a LinkHeader.

1 files changed, 2 insertions, 2 deletions

diff --git a/db/migrate/20181024224956_migrate_account_conversations.rb b/db/migrate/20181024224956_migrate_account_conversations.rb
index 12e0a70fa..9e6497d81 100644
--- a/db/migrate/20181024224956_migrate_account_conversations.rb
+++ b/db/migrate/20181024224956_migrate_account_conversations.rb
@@ -17,8 +17,8 @@ class MigrateAccountConversations < ActiveRecord::Migration[5.2]
     belongs_to :account, optional: true
     belongs_to :activity, polymorphic: true, optional: true
 
-    belongs_to :status,         foreign_type: 'Status',        foreign_key: 'activity_id', optional: true
-    belongs_to :mention,        foreign_type: 'Mention',       foreign_key: 'activity_id', optional: true
+    belongs_to :status,  foreign_key: 'activity_id', optional: true
+    belongs_to :mention, foreign_key: 'activity_id', optional: true
 
     def target_status
       mention&.status