title: migrating from rails 4.2 to 5 issue need to downgrade ActiveRecord version to work with 1 gem
body: <p>I am trying to migrate from Rails 4.2 to 5 and we have a gem called activerecord-tableless and it is not compatible with ActiveRecord 5.x so is there a way in which I can downgrade ActiveRecord version as it is not a part of Gemfile and is a core Rails dependency.
  Or I will have to look for a gem that does the same job as tableless and compatible with ActiveRecord 5.x</p>
  
  <p>I would rather not find another gem but any advise on this will be highly appreciated</p>