Fix using acts_as_tenant without Rails (#192)
Fix using acts_as_tenant without Rails (#192)

Using acts_as_tenant in a project using only ActiveRecord instead of
rails fails when a default or current tenant is not set due to the
Rails::VERSION::MAJOR check.  Check the ActiveRecord::VERSION instead.
ErwinM/acts_as_tenant,ErwinM/acts_as_tenant,ErwinM/acts_as_tenant