BikeBikeBike/app/models/comment.rb

class Comment < ActiveRecord::Base
	belongs_to :user

	def comment_object
		model_type.classify.constantize.find(model_id)
	end

	def set_model(model)
		model_type = model.class.name.tableize
		model_id = model.id
	end

	def self.for(model)
		where(model_type: model.class.name.tableize, model_id: model.id).order(created_at: :asc)
	end

	def self.create_for(model, user, comment)
		create(
			model_type: model.class.name.tableize,
			model_id: model.id,
			user_id: user.id,
			comment: comment
		)
	end

    def add_comment(user, comment)
        Comment.create_for(self, user, comment)
    end

    def comments
        Comment.for(self)
    end

    def reply?
    	model_type == 'comments'
    end
end