JBuilder_vs_ruby.rb

# customizing as_json with standalone JBuilder DSL

def as_json(options={})
  Jbuilder.encode do |json|
    graffito = self
    json.(graffito, :incident_address, :borough, :latitude, :longitude)
    json.upvotes(graffito.upvotes.count)
    json.upvoted_by(graffito.upvotes.pluck(:user_id))
  end
end

# Customizing as_json with plain old Rails

def as_json(options={})
  graffito = super(:only => [:incident_address, :borough, :latitude, :longitude])
  graffito[:upvotes] = upvotes.count
  graffito[:voted_by] = upvotes.pluck(:user_id)
  graffito
end