create_reflection

# File activerecord/lib/active_record/associations/builder/association.rb, line 36
    def self.create_reflection(model, name, scope, options, extension = nil)
      raise ArgumentError, "association names must be a Symbol" unless name.kind_of?(Symbol)

      if scope.is_a?(Hash)
        options = scope
        scope   = nil
      end

      validate_options(options)

      scope = build_scope(scope, extension)

      ActiveRecord::Reflection.create(macro, name, scope, options, model)
    end