Cache order overrides DB order

[mlarraz]

Given a countries table with two rows:

country_id	name
1	China
2	America

And a model

class Country < ActiveRecord::Base
  lookup_by :name, cache: true
end

Prior to v0.11, we'd see:

Country.first.name
# => "China"

because this actually executes a db query (which implicitly orders by insertion).

Afterwards, since Country.all hits the cache instead, we see:

Country.first.name
# => "America"

because the cache orders based on the cache key (alphabetically).

This can be overridden by using the (undocumented) :order option:

class Country < ActiveRecord::Base
  lookup_by :name, cache: true, order: :country_id
end

Country.first.name
# => "China"

but this is tedious and arguably should be the default behavior.