class Tag < ActiveRecord::Base
  has_many :taggings, dependent: :destroy
  has_many :posts, through: :taggings
end

class Tag < ActiveRecord::Base
  has_many :taggings, dependent: :destroy
  has_many :posts, through: :taggings

  has_many :interests, dependent: :destroy
  has_many :followers, through: :interests, source: :follower
end

Add followers query method for Tag model
Add followers query method for Tag model
