A sort of fast mock up of how I think you could implement business logic that would be separated from data layer and controller.

business_object.rb

class BusinessObject
  class LambdaError < StandardError; end;
  class NotImplementedError < StandardError; end;

  def initialize(lambda_hash = {})
    post_init(lambda_hash)
  end

  def perform
    raise NotImplementedError, 'must implement perform.'
  end

  private

  def post_init(lambda_hash)
    @success = lambda_hash[:success]
    @failure = lambda_hash[:failure]
  end

  def success
    begin
      @success.call
    rescue NoMethodError
      raise LambdaError, 'A lambda for success must be provided'
    end
  end

  def failure
    begin
      @failure.call
    rescue NoMethodError
      raise LambdaError, 'A lambda for failure must be provided'
    end
  end
end

naive_implementation.rb

class SaveObjekt < BusinessObject
  def initialize(objekt, lambdas)
    @objekt = objekt
    super(lambdas)
  end

  def perform
    !@objekt.nil? ? success : failure
  end
end