Add user id to blog post - ruby-on-rails

Question

I have a simple blog application. When posts are added, i want the users id to be added to the post so that when a user is logged in, he can only see his posts. The id i want to add to the post, is the id of the user currently logged in.
How and where could the id attribute be added to the posts model?
Session controller:
class SessionsController < ApplicationController
def new
end
def create
user = User.authenticate(params[:username], params[:password])
if user
session[:user_id] = user.id
redirect_to blog_url, :notice => "Logged in!"
else
flash.now.alert = "Invalid email or password"
render "new"
end
end
def destroy
session[:user_id] = nil
redirect_to root_url, :notice => "Logged out!"
end
end
Application controller:
class ApplicationController < ActionController::Base
protect_from_forgery
before_filter :authenticate
helper_method :current_user
private
def current_user
#current_user ||= User.find(session[:user_id]) if session[:user_id]
end
def authenticate
redirect_to log_in_path unless session != nil
end
end
Posts controller:
class PostsController < ApplicationController
# GET /posts
# GET /posts.json
def index
#posts = Post.all
respond_to do |format|
format.html # index.html.erb
format.json { render json: #posts }
end
end
# GET /posts/1
# GET /posts/1.json
def show
#post = Post.find(params[:id])
respond_to do |format|
format.html # show.html.erb
format.json { render json: #post }
end
end
# GET /posts/new
# GET /posts/new.json
def new
#post = Post.new
respond_to do |format|
format.html # new.html.erb
format.json { render json: #post }
end
end
# GET /posts/1/edit
def edit
#post = Post.find(params[:id])
end
# POST /posts
# POST /posts.json
def create
#post = Post.new(params[:post])
post.user_id = session
respond_to do |format|
if #post.save
format.html { redirect_to #post, notice: 'Post was successfully created.' }
format.json { render json: #post, status: :created, location: #post }
else
format.html { render action: "new" }
format.json { render json: #post.errors, status: :unprocessable_entity }
end
end
end
# PUT /posts/1
# PUT /posts/1.json
def update
#post = Post.find(params[:id])
respond_to do |format|
if #post.update_attributes(params[:post])
format.html { redirect_to #post, notice: 'Post was successfully updated.' }
format.json { head :no_content }
else
format.html { render action: "edit" }
format.json { render json: #post.errors, status: :unprocessable_entity }
end
end
end
# DELETE /posts/1
# DELETE /posts/1.json
def destroy
#post = Post.find(params[:id])
#post.destroy
respond_to do |format|
format.html { redirect_to posts_url }
format.json { head :no_content }
end
end
end
Thanks in advance!

Answer 1

In PostsController
def create
#post = current_user.posts.build(params[:post])
...
end