libr-2/app/serializers/user_serializer.rb

class UserSerializer < ActiveModel::Serializer

  attributes :id, :name, :email, :avatar, :followed, :posts_count, :likes_count, :follows_count,
             :followers_count,

  def followed
    return true if object == scope.current_user
    object.followers_ids.include? scope.current_user.try(:id)
  end

  def posts_count
    object.share_instances.count
  end

  def likes_count
    object.likes.count
  end

  def follows_count
    object.stars.count
  end

  def followers_count
    FollowRelation.where(star_id: object.id).count
  end

  def avatar
    object.avatar_url
  end


end