class AddMissingIndexesToAttachments < ActiveRecord::Migration[4.2]
def self.up
add_index :attachments, [:container_id, :container_type]
add_index :attachments, :author_id
end
def self.down
remove_index :attachments, :column => [:container_id, :container_type]
remove_index :attachments, :author_id
end
end