Controller private setter for local variable

controller_private_setter_for_local_variable.rb

class FollowingRelationshipsController < ApplicationController

  def create
    current_user.follow user
    redirect_to user
  end
  
  def destroy
    current_user.unfollow user
    redirect_to user
  end

  private
  
  def user
    @_user ||= User.find(params[:user_id]) # memoize searching in instance variable
  end
end