added support for mixed arrays of manueal joins and model associations in ActiveRecord::Base.find's :joins option
Right now it is only possible to eather supply Strings with handcoded sql join options or an Array/Hash with References to model associations. But it is not possible for example to say :joins => [:person, "ratings inner join post on ratings.post_id = posts.id"]
Added patch and tests .. https://rails.lighthouseapp.com/projects/8994-ruby-on-rails/tickets/3121-activerecordbasefind-mixed-array-of-strings-and-symbols-for-joins-option