How to use make_flaggable with STI relations

irb.rb

User.find(1).flag Tablet.find(1)
#  => #<MakeFlaggable::Flagging id: 1, flaggable_type: "Device", flaggable_id: 1, flagger_type: "User", flagger_id: 1, reason: nil, created_at: "2012-05-30 16:16:23", updated_at: "2012-05-30 16:16:23"> 

User.find(1).flagged? Tablet.find(1)
# MakeFlaggable::Flagging Load (0.4ms)  SELECT "flaggings".* FROM "flaggings" WHERE "flaggings"."flagger_id" = 1 AND "flaggings"."flagger_type" = 'User' AND "flaggings"."flaggable_type" = 'Tablet' AND "flaggings"."flaggable_id" = 1 LIMIT 1
# => false 

# :rage:
#########
# If you look at the query, it inserted the `flaggable_type` as 'Device', but is searching for 'Tablet'
# Let's trick make_flaggable into looking for the proper type:
User.find(1).flagged? Tablet.find(1).becomes(Device)

#  MakeFlaggable::Flagging Load (0.6ms)  SELECT "flaggings".* FROM "flaggings" WHERE "flaggings"."flagger_id" = 1 AND "flaggings"."flagger_type" = 'User' AND "flaggings"."flaggable_type" = 'Device' AND "flaggings"."flaggable_id" = 1 LIMIT 1
# => true 

models.rb

class Device < ActiveRecord::Base
  make_flaggable
end

class Tablet < Device
end

# Enable STI by creating a `type` column:
# rails g migration AddTypeToTablet type:string
# rake db:migrate