Rails connection issue

gistfile1.rb

# Old way, creates too many connections, breaks transactional fixtures.
# More broken on 3.2 than 3.1, didn't identify exact change though.
#
# Our suite was passing on 3.1 by accident when we initially tried to upgrade to 3.2,
# which broke everything. Since then, have added new specs that exposed the problem in 3.1.
#
# This is probably not a rails bug, but was surprising. 
module OtherModel
  def self.included(klass)
    klass.instance_eval do
      establish_connection :"other_#{Rails.env}"
    end
  end
end

class User < ActiveRecord::Base
  include OtherModel
end

# New way, use inheritance rather than a mixin.
# Works as expected.
class OtherModel < ActiveRecord::Base
  self.abstract_class = true

  establish_connection :"other_#{Rails.env}"
end

class User < OtherModel
end