Remove deprecated `name` argument from `#tables`

[c960657]

The name argument for #tables was removed in Rails 5.1.0, so let's remove it here also.

• https://github.com/rails/rails/blob/5-1-stable/activerecord/CHANGELOG.md#rails-510-april-27-2017
• https://github.com/rails/rails/commit/d5be101dd02214468a27b6839ffe338cfe8ef5f3

Together with #26 this PR removes all deprecated usage of ActiveSupport::Deprecation.warn (see https://github.com/rails/rails/pull/47354).