table_exists? not compatible with Rails 5.1

$  bin/rails db:migrate RAILS_ENV=test
DEPRECATION WARNING: Directly inheriting from ActiveRecord::Migration is deprecated. Please specify the Rails release the migration was written for:

  class CreateClustersApplicationsCertManager < ActiveRecord::Migration[4.2] (called from <main> at bin/rails:14)
== 20181101191341 CreateClustersApplicationsCertManager: migrating ============
-- create_table(:clusters_applications_cert_managers, {})
DEPRECATION WARNING: #table_exists? currently checks both tables and views. This behavior is deprecated and will be changed with Rails 5.1 to only check tables. Use #data_source_exists? instead. (called from add_index_options at /Users/stanhu/gdk/gitlab/config/initializers/postgresql_opclasses_support.rb:84)
   -> 0.0278s
== 20181101191341 CreateClustersApplicationsCertManager: migrated (0.0279s) ===