metamaps--metamaps/app/models/mapping.rb

class Mapping < ActiveRecord::Base

  scope :topicmapping, -> { where(mappable_type: :Topic) }
  scope :synapsemapping, -> { where(mappable_type: :Synapse) }

  belongs_to :mappable, polymorphic: true

  belongs_to :map, :class_name => "Map", :foreign_key => "map_id"

  belongs_to :user
  
  def user_name
    self.user.name
  end

  def user_image
    self.user.image.url
  end

  def as_json(options={})
    super(:methods =>[:user_name, :user_image])
  end
  
end