How can I improve my "newname" method

I am a student and I got the memo (without explanation) that my following code is flawed and can be much better. How would you improve my controller/reviewname method? Thank you for your time!

class ReviewController < ApplicationController

 def index
    @reviews = Review.all.order(created_at: :desc)
 end

 def newname
    @review = Review.find(params[:id])
    if @review.update_attribute(:title, sanitize(params[:title]))
      format.json { render json: { status: 200 } }
    else
      format.json { render json: { status: 500 } }
    end
 end

end