wedding_moodboard.rb

    # So I can access the following data only methods in both views and in class level validations, do I?
    # e.g.
    #     validates :event_progress,     inclusion: { in: event_progressions }
    #
    #     = f.select :owner_relationship, f.object.owner_relationships, {}, class: "form-control"
########################################################################################################################
    # 1) I tried defining as instance methods & use procs to access in validations
    # DOESNT WORK  - undefined method `event_progressions' for Forms::WeddingMoodboard:Class
    def owner_relationships
      %w{ALPHA BRAVO CHARLIE DELTA}
    end

    def event_progressions
      %w{ONE TWO THREE FOUR}
    end

    validates :event_progress,     inclusion: { in: -> (_) { event_progressions } }
    validates :owner_relationship, inclusion: { in: -> (_) { owner_relationships } }

########################################################################################################################
    # 2) Use class methods and create instance level helpers.
    def self.owner_relationships
      %w{ALPHA BRAVO CHARLIE DELTA}
    end

    def self.event_progressions
      %w{ONE TWO THREE FOUR}
    end

    def owner_relationships
      self.class.owner_relationships
    end
    def event_progressions
      self.class.owner_relationships
    end

    # Use class methods in validations, and instance methods in the view!
    validates :event_progress,     inclusion: { in: event_progressions }
    validates :owner_relationship, inclusion: { in: owner_relationships }
    # = f.select :owner_relationship, f.object.owner_relationships

########################################################################################################################
    # OR 3) Use a module, and both include and extend the class with the module, so same effect
    module SharedSelectionData
      def owner_relationships
        %w{ALPHA BRAVO CHARLIE DELTA}
      end

      def event_progressions
        %w{ONE TWO THREE FOUR}
      end
    end

    include SharedSelectionData
    extend SharedSelectionData

    #Again use class methods in validations, and instance methods in the view!
    validates :event_progress,     inclusion: { in: event_progressions }
    validates :owner_relationship, inclusion: { in: owner_relationships }
    # = f.select :owner_relationship, f.object.owner_relationships