~~Inspired by~~ Copied from Rails: http://api.rubyonrails.org/classes/ActiveRecord/Reflection/ClassMethods.html#method-i-reflect_on_all_associations

Now I see that in Rails, all associations aren't accessible from the instance, only from the class via `reflections` (eg [Stack Overflow question](http://stackoverflow.com/questions/4173333/how-to-get-activerecord-associations-via-reflection) so I certainly don't mind yanking the `associations` accessor