twitter clone controller by Rails Tutorial

twitter_controller.rb

class UsersController < ApplicationController
 before_filter :authenticate, :except => [:show, :new, :create]
 before_filter :correct_user, :only => [:edit, :update]
 before_filter :admin_user, :only => :destroy
  
 def index
  @title = "All users"
  @users = User.paginate(:page => params[:page])
 end
  
 def show
  @user = User.find(params[:id])
  @microposts = @user.microposts.paginate(:page => params[:page])
  @title = @user.name
 end
  
 def new
  @user = User.new
  @title = "Sign up"
 end
  
 def create
  @user = User.new(params[:user])
  if @user.save
   sign_in @user
   flash[:success] = "Welcome to the Sample App!"
   redirect_to @user
  else
   @title = "Sign up"
   render 'new'
  end
 end
  
 def edit
  @user = User.find(params['id'])
  @title = 'Edit user'
 end
  
 def update
  @user = User.find(params[:id])
  if @user.update_attributes(params[:user])
   flash[:success] = "Profile updated!"
   redirect_to @user
  else
   @title = "Edit user"
   render 'edit'
  end
 end
  
   def following
    @title = "Following"
    @user = User.find(params[:id])
    @users = @user.following.paginate(:page => params[:page])
    render 'show_follow'
   end
 
   def followers
    @title = "Followers"
    @user = User.find(params[:id])
    @users = @user.followers.paginate(:page => params[:page])
    render 'show_follow'
   end
 
  
 def destroy
  User.find(params[:id]).destroy
  flash[:success] = "User destroyed."
  redirect_to users_path
 end
  
 private
   
  def correct_user
   @user = User.find(params[:id])
   redirect_to(root_path) unless current_user?(@user)
  end
   
  def admin_user
   redirect_to(root_path) unless current_user.admin?
  end
 
end