Add published column to Sequel test db schema

Author: shioyama

spec/sequel/schema.rb

@@ -129,6 +129,7 @@ def migrate(*)
             DB.create_table? :container_posts do
               primary_key :id
               jsonb       :translations, default: '""'
+              TrueClass   :published
               DateTime    :created_at, allow_null: false
               DateTime    :updated_at, allow_null: false
             end